| S.no | Company Name | Founded | Country |
|---|---|---|---|
| 1 | Struthers-Dunn Inc. | USA | |
| 2 | SE Relays | USA | |
| 3 | Watlow | USA | |
| 4 | Hampton Controls Inc. | USA | |
| 5 | Delta Manufacturing Co. Inc. | USA | |
| 6 | Heaters Controls & Sensors Ltd. | USA | |
| 7 | Comus International | USA | |
| 8 | National Plastic Heater | USA | |
| 9 | PICS INC | USA | |
| 10 | Mercury Displacement Industries Inc. (MDI Inc.) | USA |
