Constructed of tough black thermoset (UL94V0). Includes 3 springs for various fuse sizes and spring-locked, bayonet type knob. Supplied with 15" loop of 14 gauge red wire. Use with Glass SFE 7 1/2, 9, 14, 20, AGA, AGC, AGW and AGX Fuses up to 20 amps when proper spring is installed.(see part B. in image)