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UMT 20x25 black / N38 - board holder

board holder

Catalog no 230263

GTIN/EAN: 5906301814269

5.00
Diameter Ø
20 mm [±1 mm]
Height
25 mm [±1 mm]
Weight
7 g
Coating
[NiCuNi] Nickel

How we measure these parameters — certificates and measurements

product parameters »

2.84 zł net / pcs

3.49 zł with VAT (23% VAT) / pcs

price for transport

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Frequently asked questions

How many sheets of paper will one magnetic pin hold?
The category description quotes <strong>up to 20 sheets of A4</strong>, and that is the number to start from. It is not fixed: a magnet holds more firmly on a thicker base — a fridge door or a solid whiteboard backing gives more than the thin sheet behind a cheap dry-wipe board. Paper matters too: twenty sheets of office weight is not the same as twenty sheets of coated stock. For thicker stacks and folders take a larger size, 20x25 or 29x38 mm — a bigger contact area than 12x20.
Will a magnetic pin stick to any board - whiteboard, glass, cork?
No, not to every surface — a magnet only holds on a ferromagnetic material, which usually means whiteboards and glass boards that have a steel sheet underneath. Plain glass without a metal backing won't attract the magnet at all. Cork boards mostly lack a metal layer too, so the pin won't stick unless the manufacturer specifically states the board is magnetic. Before buying, a simple test helps — try any magnet against the board in the shop or at home.
Will the magnet leave a mark or scratch the board or the fridge?
No, under normal use the pin leaves no lasting mark or scratch — the bottom of the magnet has an ergonomic, smooth shape designed for contact with smooth surfaces like a lacquered fridge door or a laminated board. The risk appears only when sliding the magnet across a surface with trapped grit or other hard particles caught between the base and the board — that can cause a light scratch, the same as with any object dragged across a painted surface. Wiping the magnet's base regularly removes this risk.
What is the difference between the 12x20 and 20x25 sizes, and which one suits an office?
The main difference is holding strength and grip comfort — the UMT 20x25 has a larger magnet surface, so it holds a thicker stack of sheets more firmly and is easier to grab with your fingers. The UMT 12x20 is compact and works better where board space is tight, for example with many small notes side by side. For a typical office board holding a few sheets and schedules, both sizes work fine — the choice mainly comes down to whether holding strength or fitting more pins side by side matters more.
Are magnetic pins suitable for large-format maps and plans?
Yes, they work well for that — the larger UMT 20x25 variant is well suited to maps and plans hung on magnetic boards in offices, on construction sites, or in planning rooms, since it holds heavier, stiffer paper better than the smaller pin. For a large format, it helps to place several pins along the corners and edges of the plan rather than just one in the center — this spreads the pressure and prevents the paper from sagging under its own weight.

Guides from the knowledge base

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Specifications and structure of a neodymium magnet can be estimated using our power calculator.

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Detailed specification - UMT 20x25 black / N38 - board holder

Specification / characteristics - UMT 20x25 black / N38 - board holder

properties
properties values
Cat. no. 230263
GTIN/EAN 5906301814269
Production/Distribution Dhit sp. z o.o.
ul. Zielona 14 05-850 Ożarów Mazowiecki PL
Country of origin Poland / China / Germany
Customs code 85059029
Diameter Ø 20 mm [±1 mm]
Height 25 mm [±1 mm]
Weight 7 g
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±1 mm

Magnetic properties of material N38

Specification / characteristics UMT 20x25 black / N38 - board holder
properties values units
Remanence Br ? 12.2-12.6 kGs
Remanence Br ? 1220-1260 mT
Coercivity bHc ? 10.8-11.5 kOe
Coercivity bHc ? 860-915 kA/m
Intrinsic coercivity iHc ≥ 12 kOe
Intrinsic coercivity iHc ≥ 955 kA/m
Energy product BHmax ? 36-38 BH max MGOe
Energy product BHmax ? 287-303 BH max KJ/m
Maximum working temperature ? ≤ 80 °C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C
properties values units
Vickers hardness ≥550 Hv
Density ≥7.4 g/cm3
Curie Temperature TC 310 °C
Curie Temperature TF 590 °F
Specific resistance 150 μΩ⋅cm
Bending strength 250 MPa
Compressive strength 1000~1100 MPa
Thermal expansion parallel (∥) to orientation (M) (3-4) x 10-6 °C-1
Thermal expansion perpendicular (⊥) to orientation (M) -(1-3) x 10-6 °C-1
Young's modulus 1.7 x 104 kg/mm²
Technical and environmental data

Chemical composition

iron (Fe) 64% – 68%
neodymium (Nd) 29% – 32%
boron (B) 1.1% – 1.2%
dysprosium (Dy) 0.5% – 2.0%
coating (Ni-Cu-Ni) < 0.05%

Ecology and recycling (GPSR)

recyclability (EoL) 100%
recycled raw materials ~10% (pre-cons)
carbon footprint low / zredukowany
waste code (EWC) 16 02 16
Safety card (GPSR)
responsible entity
Dhit sp. z o.o.
ul. Kościuszki 6A, 05-850 Ożarów Mazowiecki
tel: +48 22 499 98 98 | e-mail: bok@dhit.pl
batch number/type
id: 230263-2026
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Pulling force

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Magnetic pins stand out with an ergonomic shape that facilitates gripping and moving them. Small size hides great power - one pin works better than a handful of regular magnets. They are aesthetic, colorful, and do not scratch the board surface thanks to a smooth base.
Despite inconspicuous size, one pin with a neodymium magnet can hold even 15-20 A4 paper sheets. They guarantee that your notes and important information will stay in place.
Pins are ideal for whiteboards, magnetic boards, and glass boards in offices and schools. Available vivid colors facilitate information coding, prioritizing, and task organization. Note: Special, even stronger neodymium magnets are needed for glass boards.
Caution should be exercised and the product kept away from infants. For older children, they are a great scientific aid for physics experiments.
We offer a wide color range: red, blue, green, yellow, white, black, and many others. Pins are made of durable plastic with vivid colors that do not fade.

Advantages and disadvantages of neodymium magnets.

Advantages

Apart from their consistent holding force, neodymium magnets have these key benefits:
  • They do not lose power, even over approximately 10 years – the drop in lifting capacity is only ~1% (based on measurements),
  • They maintain their magnetic properties even under close interference source,
  • In other words, due to the aesthetic layer of gold, the element gains a professional look,
  • Magnetic induction on the working layer of the magnet turns out to be maximum,
  • Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
  • Thanks to flexibility in forming and the capacity to customize to complex applications,
  • Significant place in future technologies – they are used in hard drives, electromotive mechanisms, precision medical tools, and modern systems.
  • Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Limitations

Disadvantages of NdFeB magnets:
  • Brittleness is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a steel housing, which not only secures them against impacts but also raises their durability
  • Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
  • Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
  • Due to limitations in producing threads and complex shapes in magnets, we recommend using cover - magnetic holder.
  • Health risk resulting from small fragments of magnets pose a threat, if swallowed, which gains importance in the context of child health protection. It is also worth noting that tiny parts of these products can complicate diagnosis medical after entering the body.
  • Due to neodymium price, their price exceeds standard values,

Pull force analysis

Maximum magnetic pulling force – what contributes to it?

Information about lifting capacity was determined for ideal contact conditions, taking into account:
  • with the application of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
  • whose thickness equals approx. 10 mm
  • with an ground contact surface
  • with total lack of distance (without impurities)
  • under axial application of breakaway force (90-degree angle)
  • in neutral thermal conditions

Practical aspects of lifting capacity – factors

Real force is influenced by specific conditions, including (from priority):
  • Air gap (betwixt the magnet and the metal), as even a microscopic clearance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to paint, rust or debris).
  • Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of nominal force).
  • Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
  • Material composition – not every steel reacts the same. Alloy additives worsen the attraction effect.
  • Base smoothness – the more even the plate, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
  • Thermal conditions – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the holding force is lower. In addition, even a small distance between the magnet and the plate reduces the holding force.

H&S for magnets
Pinching danger

Risk of injury: The attraction force is so great that it can result in hematomas, crushing, and even bone fractures. Use thick gloves.

ICD Warning

Health Alert: Neodymium magnets can deactivate heart devices and defibrillators. Do not approach if you have medical devices.

GPS Danger

An intense magnetic field negatively affects the functioning of magnetometers in smartphones and GPS navigation. Do not bring magnets near a device to prevent breaking the sensors.

Maximum temperature

Do not overheat. Neodymium magnets are sensitive to heat. If you require operation above 80°C, ask us about special high-temperature series (H, SH, UH).

Data carriers

Very strong magnetic fields can erase data on payment cards, HDDs, and storage devices. Keep a distance of at least 10 cm.

Eye protection

Despite metallic appearance, neodymium is brittle and cannot withstand shocks. Do not hit, as the magnet may shatter into hazardous fragments.

Nickel allergy

Warning for allergy sufferers: The nickel-copper-nickel coating contains nickel. If skin irritation occurs, immediately stop working with magnets and wear gloves.

Caution required

Before use, check safety instructions. Sudden snapping can break the magnet or hurt your hand. Think ahead.

Danger to the youngest

These products are not toys. Swallowing several magnets can lead to them pinching intestinal walls, which constitutes a critical condition and requires urgent medical intervention.

Fire warning

Mechanical processing of neodymium magnets poses a fire risk. Magnetic powder oxidizes rapidly with oxygen and is hard to extinguish.

Caution! Want to know more? Check our post: Are neodymium magnets dangerous?