The RB2257 is a vinyl-insulated locking fork terminal for wire range #18 - #14 AWG. Locking fork terminals have a specially designed tongue that lets them go on like a fork and stay on like a ring. Length .97 inches, .29 inches width, maximum insulation .200 inches, bolt hole #10. The terminal is high-conductivity electrolytic copper, electro-tin plated, with color-coded insulation. Recommended tool ERG4001.