| Number | Name | Date | Kind |
|---|---|---|---|
| 1402769 | Hirshfeld | Jan 1922 | |
| 3012090 | Robbins | Dec 1961 |
| Entry |
|---|
| Acro-Mu Precision Snap Action Switches, Cat. No. 98, May 22, 1956, p. 31, Type M Switches. |
| Gould Electronics, General Cat. 1983, p. P15, Type P Long Range Proximity Sensors. |