Fuse block with midget open-style. Insulators are glass-filled polycarbonate (GFPC) with verified dielectric strength in excess of 2500 V. Screw with double quick-connects at both ends. #10-14 copper wire. Fuse blocks feature a unique adder block which can be snapped onto 3 pole blocks to form multi-pole segmented blocks of as many poles as desired. All fuse clips are made of high conductivity tin-plated copper alloy.