Safe and Reliable Insulation - The red nut connector is made of high-quality nylon shell and metal spring, with tough thermoplastic and UL94V-2 flame retardant shell. The tough thermoplastic shell protector can withstand extreme environments and temperatures up to 221F (105C). Insulated plastic, insulated plastic, insulated plastic is safe when connecting wires. Quick Connection - Heavy-duty wire nuts are perfect for connecting wires, no soldering required, just push the stripped conductor into the wire cap and tighten, no pre-twisting of wires, soldering or electrical tape, no tools required. Electrical nuts can quickly connect automotive, building wiring, lighting fixtures and signs. Each connector is marked with model and specification for easy identification. The wing nut design allows for easy installation and removal. The connectors have excellent performance. The high-quality copper in the wire cover not only has good conductivity, but also increases the current flow and reduces voltage instability. Improve the and insulation of electrical projects. Rated voltage up to 600 volts for construction, lighting fixtures and signs use voltage of 1000 volts. These wing wire connectors are reusable, safe and reliable. The wire nuts are with perfect flame retardant material to prevent wires from contacting other wires or exposed metal surfaces, well avoid dangerous faults and short circuits. They have a sturdy construction and strong grip to hold the wires in place. They are a good helper for homeowners or engineers who work on home theater projects, or for HVAC, lamps, audio, speaker wire, stereo wiring, automotive, marine wiring, home wiring, and any type of electrical work, etc. Colour:Red Material:nylon+Metal Package Contents: 1set x wire nuts(600 pieces) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.