Square D (Schneider Electric) RZM031RB. Square D™ Zelio™ Relay Protection Module, For Use With: RPZ and RXZ Relay, Specifications: 6 to 24 VDC, 3-1/2 in L x 2-1/2 in W x 1/2 in H Dimensions. Additional Description: SQD -RZM031RB (N) RELAY MODULE 6-24VDC RSB +OPTIONS +OPTIONS NON-CANCELABLE, NON-RETURNABLE. Catalog Description: Protection module, Harmony, diode+green LED, for all sockets, 6 24V DC.