These B-Connectors (AKA Beans, Beanies) are used to splice low voltage wires, and designed to accept up to four strands of solid or stranded 22 AWG wire unstripped. Simply insert wire and crimp. It is great for alarm and telephone wiring and installation of most communication curcuit equipment. Materials breakdown as follows- Outer Shell: Plastic Type - Heat Shrink Tubing Metal Housing: Brass Inner Sleeve: Beryllium Copper plated with Bright Nickel Contact Resistance: 10 milliohms initial Dielectric: 1000 V Strength of Joint: 9 lbs. These wire splices have been utilized in the communications industry for years and years. They provide a dependable splice.