The RF10721 is a large ring terminal insulated with high dielectric-strength nylon for aircraft wire size 4AN. These ring terminals have funneled barrel entry, deep internal serrations, and overlapping seams. Length 1.80 inches, .62 inches width, maximum insulation .380 inches, bolt hole 5/16 inches. The terminal is high-conductivity electrolytic copper, electro-tin plated, with color-coded insulation. Installing tool TBM6S.