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UMT 20x25 white / N38 - board holder

board holder

Catalog no 230262

GTIN/EAN: 5906301814252

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

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2.84 zł net / pcs

3.49 zł with VAT (23% VAT) / pcs

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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

Want to talk magnets?

Call us now +48 888 99 98 98 alternatively let us know using contact form the contact section.
Specifications and structure of a neodymium magnet can be estimated using our power calculator.

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Physical properties - UMT 20x25 white / N38 - board holder

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

properties
properties values
Cat. no. 230262
GTIN/EAN 5906301814252
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 white / 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
Engineering data and GPSR

Elemental analysis

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%

Sustainability

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: 230262-2026
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This shape makes operating a whiteboard convenient, fast, and does not break nails. Inside the plastic housing is a very strong neodymium magnet, not weak ferrite. It's a professional choice for office, school, conference room, and home.
They will easily hold a heavier calendar, map, or diploma on the fridge. They do not slide down under the weight of a single sheet like cheap advertising substitutes.
At home, they will serve to attach shopping lists, bills, photos, and drawings to the fridge. You can use them for board games (as pawns) and educational games with children. Note: Special, even stronger neodymium magnets are needed for glass boards.
Although the magnet is tightly sealed in a plastic housing, the product is small and poses a swallowing risk. 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.

Strengths and weaknesses of neodymium magnets.

Strengths

Besides their high retention, neodymium magnets are valued for these benefits:
  • They have constant strength, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
  • They show high resistance to demagnetization induced by external magnetic fields,
  • A magnet with a smooth gold surface has better aesthetics,
  • They are known for high magnetic induction at the operating surface, which improves attraction properties,
  • Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
  • Possibility of detailed shaping and adapting to defined conditions,
  • Fundamental importance in future technologies – they are used in data components, electric drive systems, medical devices, as well as complex engineering applications.
  • Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in compact dimensions, which makes them useful in small systems

Limitations

Cons of neodymium magnets: application proposals
  • Brittleness is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a special holder, which not only protects them against impacts but also increases their durability
  • Neodymium magnets decrease 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 stability even at temperatures up to 230°C
  • When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
  • Limited ability of producing threads in the magnet and complicated shapes - recommended is cover - magnetic holder.
  • Health risk related to microscopic parts of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small elements of these magnets are able to be problematic in diagnostics medical in case of swallowing.
  • Due to complex production process, their price is relatively high,

Lifting parameters

Optimal lifting capacity of a neodymium magnet – what it depends on?

The lifting capacity listed is a measurement result performed under specific, ideal conditions:
  • using a sheet made of low-carbon steel, serving as a circuit closing element
  • whose thickness is min. 10 mm
  • with an ground touching surface
  • without any air gap between the magnet and steel
  • under vertical application of breakaway force (90-degree angle)
  • at standard ambient temperature

Practical lifting capacity: influencing factors

In real-world applications, the actual lifting capacity is determined by many variables, ranked from most significant:
  • Distance (betwixt the magnet and the metal), because even a microscopic distance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
  • Force direction – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
  • Metal thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of converting into lifting capacity.
  • Metal type – not every steel reacts the same. Alloy additives weaken the attraction effect.
  • Base smoothness – the more even the surface, the better the adhesion and higher the lifting capacity. Unevenness acts like micro-gaps.
  • Temperature influence – hot environment reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, however under parallel forces the holding force is lower. Moreover, even a small distance between the magnet and the plate decreases the load capacity.

Safe handling of NdFeB magnets
Conscious usage

Before use, check safety instructions. Uncontrolled attraction can break the magnet or injure your hand. Be predictive.

Data carriers

Data protection: Neodymium magnets can ruin data carriers and sensitive devices (pacemakers, medical aids, timepieces).

Crushing risk

Big blocks can break fingers instantly. Do not put your hand between two attracting surfaces.

Skin irritation risks

It is widely known that nickel (the usual finish) is a potent allergen. If your skin reacts to metals, avoid direct skin contact and choose encased magnets.

Medical interference

Individuals with a pacemaker have to maintain an safe separation from magnets. The magnetic field can interfere with the functioning of the implant.

Shattering risk

NdFeB magnets are ceramic materials, meaning they are prone to chipping. Impact of two magnets leads to them breaking into small pieces.

Phone sensors

GPS units and smartphones are highly susceptible to magnetic fields. Direct contact with a powerful NdFeB magnet can decalibrate the sensors in your phone.

Keep away from children

NdFeB magnets are not toys. Eating several magnets can lead to them connecting inside the digestive tract, which poses a critical condition and requires immediate surgery.

Machining danger

Fire warning: Rare earth powder is highly flammable. Do not process magnets without safety gear as this may cause fire.

Heat sensitivity

Standard neodymium magnets (grade N) undergo demagnetization when the temperature goes above 80°C. This process is irreversible.

Danger! Details about risks in the article: Magnet Safety Guide.