Littelfuse 656 and 658 Series Fuse Blocks are molded base fuse blocks compatible with 5mm x 20mm fuse sizes. These fuse blocks feature <5mΩ contact resistance, >3kV dielectric strength at 50Hz (1 min), and >4kV impulse withstand voltage between line and neutral. The 656 and 658 series fuse blocks offer >10MΩ insulation resistance at 500VDC (1 min) and are vibration resistant, per IEC 60068-2-6, test Fc. The clip terminals of the fuse blocks are made of tin-plated copper alloy, and the clip frames are of either UL94 V-0 rated black, thermoplastic, or LCP. These fuse blocks operate within the -40°C to 85°C temperature range and are RoHS-compliant and lead-free.