HWB12 Sealed Power Distribution Modules Littelfuse HWB12 Sealed Power Distribution Modules (PDMs) are hard-wired boxes featuring 12 cavities that accept 2.8mm fuse and relay components. These PDMs are ideal for accessory circuits and overflow circuits from a designer's main PDM. Littelfuse HWB12 can hold plug-in components, including MINI fuses, MINI format circuit breakers, 4-pin single-throw relays, and 5-pin double-throw relays. The HWB12 features durable construction, an IP67/IP69K rating, and a compact size. Users can customize their circuitry utilizing direct wire-to-component connections that are crimped to the wire harness with grommets to seal the bottom of the module.