The industry standard twist-on connector has top quality performance and durability. Color-coded for easy size selection. Tight, square-wire spring makes quick, secure connections for positive continuity. Tough, thermoplastic shell shields against environmental extremes. Resists chemical action from hydrocarbons, diluted acid or alkaline solutions. Flame-retardant properties resist heat distortion up to 105°C (221°F). High-dielectric shell features deep skirt design to prevent exposure of bare wire. Copper-to-copper connections only.