Helwig Carbon part numbers starting 400
| 4000CA | Bulletin 646 size d | Helwig Carbon | ||
| 4001CA | Bulletin 646 size c | Helwig Carbon | ||
| 4002CA | Bulletin 646 size c | Helwig Carbon | ||
| 4003CA | Bulletin 646 size b stationary contactor | Helwig Carbon | ||
| 4004CA | Bulletin 646 size b short stationary contactor | Helwig Carbon |