Square D™ Surgelogic™ HWB Surge Protective Devices (SPDs) deliver specification grade performance for critical branch panel applications. This multi-phase surge suppression system provides surge impulse mitigation in a durable UL/NEMA 4X enclosure. These devices are designed to provide high-quality surge suppression for a wide variety of commercial, industrial, OEM or institutional applications. The HWB is a UL 1449 Type 1 listed device.