The RF4-38 is a large ring terminal insulated with high dielectric-strength nylon for wire size #4 AWG. These ring terminals have funneled barrel entry, deep internal serrations, and overlapping seams. Length 1.84 inches, .62 inches width, maximum insulation .510 inches, bolt hole 3/8 inches. The terminal is high-conductivity electrolytic copper, electro-tin plated, with color-coded insulation, rated for 105°C max temperature. Installing tool TBM6S.