YSHIELD M2L magnetic shielding film

Declared attenuation

Each figure is the manufacturer's declaration for the frequency and the layer or coat count named next to it. The percentage is computed from the dB value, not quoted separately.

power frequency (50/60 Hz) magnetic field, single layer

12.1 dB — removes 75.2% of the field amplitude

power frequency (50/60 Hz) magnetic field, two layers

16.3 dB — removes 84.7% of the field amplitude

power frequency (50/60 Hz) magnetic field, three layers

19.5 dB — removes 89.4% of the field amplitude

power frequency (50/60 Hz) magnetic field, four layers

21.7 dB — removes 91.8% of the field amplitude

Test method

Manufacturer-declared magnetic-field attenuation per layer count, quoted with the corresponding percentage reduction in field amplitude. These are amplitude ratios, not the power ratios used for the same manufacturer's RF products.

Construction

Two-layer high-permeability alloy film protected with laminating foil on both sides, 21 cm wide.

Typical application

• Local shielding of a transformer, riser or supply cable
• Intermediate layer in a wall, floor or ceiling build-up
• Shielding a bed head from a known magnetic source

What the figure does not cover

• Magnetic shielding works by diverting flux, so a flat film only helps where it sits between the source and the person; it does not enclose a room
• 12.1 dB is a factor of about four in field, not the thousandfold reduction RF materials are quoted at — magnetic fields at power frequency are the hardest case in shielding
• High-permeability alloys lose permeability if kinked, folded, hammered or drilled, and the loss is permanent and invisible
• Declared per flat layer in the manufacturer's fixture: geometry, distance and source orientation change the installed result more than layer count does
• Nothing here addresses RF; the field type is different and so is the material

What these figures are

Every attenuation value on this page is the manufacturer's own declaration for a flat sample in a test fixture, reproduced so that products can be compared on the same terms. It is not a regulatory limit, not an independent test, and not a prediction of what a meter will read after installation — an installed shield is set by its weakest path, so the only figure that describes a room is a before-and-after measurement of that room.

Related records

• High-permeability alloy (mu-metal) magnetic shielding

  The only material class that meaningfully attenuates power-frequency magnetic fields, and even then typically by a factor of two to five in a retrofit — which is why distance and source correction are preferred.

  Shielding & remediation

• Shielding attenuation

  Decibels of field reduction provided by a material. Every 10 dB is a factor of 10 in power density: 30 dB removes 99.9%, 10 dB removes 90%.

  Quantities & units

• Magnetic flux density

  The quantity an ELF gaussmeter reports, expressed in milligauss or microtesla, used to assess wiring, transformers and power lines. 1 µT = 10 mG.

  Quantities & units

Sources

1. yshield-product-overview YSHIELD product overview with technical data and shielding attenuation — YSHIELD GmbH & Co. KG, 2026. manufacturer, link checked 2026-08-12.