RK Electronics MVPL-24A-A1C Phase Failure Relay. R-K Electronics Voltage Monitor Relay 1/3-Phase Multi-Range Series: MVPL 24 VAC 10 A 50/60 Hz Frequency SPDT Contact Configuration 8 Pins Plug-In Mounting 3.6 in H x 2.3 in W x 1.8 in D Dimensions. Additional Description: RKEC-MVPL-24A-A1C MULTI-RANGE VOLT RLY 24VAC. Catalog Description: Multi-Range 3 Phase Voltage Monitor (200 to 240VAC 1Ø and 200 to 480VAC 3Ø) 24VAC Supply 8-Pin Base SPDT Contacts Socket & Holddown Included.