RPM Series The RPM power relay range includes sockets with mixed contact terminals and protection modules. 15 A relays with 1, 2, 3 and 4 CO (SPDT, DPDT, 3PDT and 4PDT) contacts Protection modules (diode, RC circuit or varistor) or 1 timer module (for use only with 3-pole or 4-pole sockets) Metal hold-down clip for single-contact relays