Actuation Distances for UM-0018-M Reed Switches
For easy selection of AT band and Magnet for an application, we offer Actuation distances for the UM-0018-M Reed Switch in, Cropped, SMD, and Horizontal Mount Lead formations. The various combinations of standard AT Bands and magnets are covered, from the lower AT bands to the higher AT bands. Each AT band lists actuation distances when actuated with our standard magnets. Although some of the AT band / magnet combinations of the UM-0018-M Reed Switch will produce similar actuating distances, selecting the right AT band and magnet for an application is important. Our Usage Notes below address these topics.
All distances given are in mm and standard tolerances of ±0.5 mm apply.
Actuation Distances for Cropped Leads

Operate Band 7-12 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | 2.0 – 3.5 | 2.5 – 4.0 |
NDR-S | 6.0 x 2.5 x 2.5 | 6.0 – 7.5 | 6.5 – 7.0 |
NDR-M | 8.0 x 3.0 x 3.0 | 8.0 – 9.5 | 8.5 – 10.0 |
NDR-L | 19.0 x 4.0 x 4.0 | 13.0 – 17.5 | 14.0 – 18.0 |
NDC-T | Ø2.0 x 4.0 | 3.0 – 4.5 | 3.5 – 5.5 |
NDC-S | Ø3.0 x 7.0 | 7.0 – 8.0 | 7.5 – 8.5 |
NDC-M | Ø4.0 x 10.0 | 10.5 – 12.0 | 11.5 – 13.5 |
NDC-L | Ø8.0 x 15.0 | 20.5 – 24.0 | 21.5 – 25.0 |
Operate Band 12-17 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | 2.0 – 2.5 | 2.0 – 3.5 |
NDR-S | 6.0 x 2.5 x 2.5 | 6.0 – 7.5 | 6.5 – 7.0 |
NDR-M | 8.0 x 3.0 x 3.0 | 8.0 – 9.5 | 8.5 – 10.0 |
NDR-L | 19.0 x 4.0 x 4.0 | 13.0 – 17.5 | 14.0 – 18.0 |
NDC-T | Ø2.0 x 4.0 | 3.0 – 4.5 | 3.5 – 4.0 |
NDC-S | Ø3.0 x 7.0 | 7.0 – 8.0 | 7.5 – 8.5 |
NDC-M | Ø4.0 x 10.0 | 10.5 – 12.0 | 11.5 – 13.5 |
NDC-L | Ø8.0 x 15.0 | 20.5 – 24.0 | 21.5 – 24.0 |
Actuation Distances for SMD Formed Leads

Operate Band 7-12 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | 3.0 – 3.5 | 3.5 – 4.0 |
NDR-S | 6.0 x 2.5 x 2.5 | 7.0 – 7.5 | 7.5 – 8.0 |
NDR-M | 8.0 x 3.0 x 3.0 | 8.5 – 10.0 | 9.0 – 11.0 |
NDR-L | 19.0 x 4.0 x 4.0 | 14.0 – 17.0 | 15.0 – 18.0 |
NDC-T | Ø2.0 x 4.0 | 10.5 – 13.0 | 11.0 – 14.0 |
NDC-S | Ø3.0 x 7.0 | 3.5 – 4.5 | 4.5 – 5.0 |
NDC-M | Ø4.0 x 10.0 | 7.0 – 8.5 | 7.5 – 9.0 |
NDC-L | Ø8.0 x 15.0 | 21.0 – 25.0 | 22.0 – 26.5 |
Operate Band 12-17 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | 2.5 – 3.0 | 2.0 – 3.5 |
NDR-S | 6.0 x 2.5 x 2.5 | 6.0 – 7.0 | 6.5 – 7.5 |
NDR-M | 8.0 x 3.0 x 3.0 | 8.0 – 8.5 | 8.5 – 9.0 |
NDR-L | 19.0 x 4.0 x 4.0 | 13.0 – 14.0 | 14.0 – 15.5 |
NDC-T | Ø2.0 x 4.0 | 3.0 – 3.5 | 3.5 – 4.0 |
NDC-S | Ø3.0 x 7.0 | 6.5 – 7.5 | 7.0 – 8.0 |
NDC-M | Ø4.0 x 10.0 | 10.0 – 10.5 | 10.5 – 11.5 |
NDC-L | Ø8.0 x 15.0 | 20.0 – 21.0 | 21.0 – 23.0 |
Actuation Distances for Horizontal Mounting on PCBs

Operate Band 7-12 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | 3.0 – 3.5 | 3.5 – 4.0 |
NDR-S | 6.0 x 2.5 x 2.5 | 7.0 – 9.5 | 7.5 – 10.0 |
NDR-M | 8.0 x 3.0 x 3.0 | 10.0 – 11.5 | 10.5 – 12.5 |
NDR-L | 19.0 x 4.0 x 4.0 | 17.0 – 20.5 | 18.0 – 22.0 |
NDC-T | Ø2.0 x 4.0 | 4.0 – 5.0 | 4.5 – 6.0 |
NDC-S | Ø3.0 x 7.0 | 8.0 – 9.5 | 8.5 – 10.0 |
NDC-M | Ø4.0 x 10.0 | 12.5 – 15.0 | 13.0 – 15.5 |
NDC-L | Ø8.0 x 15.0 | 24.5 – 30.0 | 25.0 – 31.0 |
Operate Band 12-17 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | 2.5 – 3.5 | 3.0 – 4.0 |
NDR-S | 6.0 x 2.5 x 2.5 | 6.0 – 7.5 | 6.5 – 8.0 |
NDR-M | 8.0 x 3.0 x 3.0 | 9.5 – 10.5 | 10.0 – 11.5 |
NDR-L | 19.0 x 4.0 x 4.0 | 15.0 – 18.0 | 16.0 – 19.0 |
NDC-T | Ø2.0 x 4.0 | 3.5 – 4.0 | 4.0 – 5.0 |
NDC-S | Ø3.0 x 7.0 | 7.5 – 8.5 | 8.0 – 9.5 |
NDC-M | Ø4.0 x 10.0 | 12.0 – 13.0 | 12.5 – 14.0 |
NDC-L | Ø8.0 x 15.0 | 23.0 – 25.0 | 24.0 – 26.5 |
Actuation Distances for Vertical Mounting on PCBs

Operate Band 7-12 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | ||
NDR-S | 6.0 x 2.5 x 2.5 | ||
NDR-M | 8.0 x 3.0 x 3.0 | ||
NDR-L | 19.0 x 4.0 x 4.0 | ||
NDC-T | Ø2.0 x 4.0 | ||
NDC-S | Ø3.0 x 7.0 | ||
NDC-M | Ø4.0 x 10.0 | ||
NDC-L | Ø8.0 x 15.0 |
Operate Band 12-17 (AT)
Magnet | Dimensions | Operate Distance | Release Distance |
NDR-T | 4.0 x 1.5 x 1.5 | ||
NDR-S | 6.0 x 2.5 x 2.5 | ||
NDR-M | 8.0 x 3.0 x 3.0 | ||
NDR-L | 19.0 x 4.0 x 4.0 | ||
NDC-T | Ø2.0 x 4.0 | ||
NDC-S | Ø3.0 x 7.0 | ||
NDC-M | Ø4.0 x 10.0 | ||
NDC-L | Ø8.0 x 15.0 |
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