HWB18 18-Way Compact Power Distribution Modules Littelfuse HWB18 18-Way Compact Hard-Wired Power Distribution Modules (PDMs) feature 18 cavities that accept 2.8mm fuse and relay components. HWB18 is ideal for accessory circuits and overflow circuits from a designer's main PDM. Littelfuse HWM18 can hold plug-in components, including MINI fuses, MINI format circuit breakers, 4-pin single throw relays, and 5-pin double throw relays. HWB18 offers 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.