The RCS10-10X is a ring terminal for wire range #12 - #10 AWG. These terminals are self-insulated with heat-shrinkable polyolefin and internally coated sealant. Upon completed installation, a fully sealed connection protects the joint against the degrading effects of galvanic action, corrosion, and environmental exposure - length 1.34 inches, width .37 inches, bolt hole #10, and maximum insulation .250 inches. The ring terminal is made of high-conductivity electrolytic copper, electro-tin plated. They recommended tool ERG4255.