Road Power 400C-2 Booster Cable Clamps, 2-Pack, Red/Black, 500-Amps. Vinyl coated steel clamps. Handle length is about 7-inches. Conductors are copper plated steel. For use with 6 and 12-volt batteries. Recommended for 4,6, or 8 gauge cables. Clamps work with top post and side terminal batteries. The Road Power (R) brand is a registered trademark of Coleman Cable Inc.