The most popular range in the STX series offering, the Surge-Trap® Type 1 STXR meets requirements for UL1449 Fourth Edition and is ideal for the replacement of older surge arrestors. The STXR Series SPD feature TPMOV® technology inside making them the safest product available. With a small, compact design and line or load installation flexibility the STXR series is the perfect fit for branch panel and/or individual equipment protection., 120V, L-G, L-N, Single Phase, LED and Remote Audible Alarm Audible Alarm 50 kA per phase