Surge-Trap Pluggable STP Series Surge Protective Device (SPD) is a no-fuse, failsafe surge suppressor featuring Mersen’s TPMOV® technology inside – no need for additional overcurrent protection. DIN-rail mountable featuring a fail-safe self-protected design, visual indicator, and a small footprint. A remote indicator provides status to critical control circuitry. High short circuit current rating makes it suitable for most industrial control panels.