4-way design: the car battery clamps have 4 terminals designed for multi-channel connection. The wiring is convenient, the connection is firm and it is not easy to be damaged. High quality: The car battery clamps are made of copper, which is corrosion resistant and durable. Easy to wire, has good electrical conductivity. Size: Suitable for wire diameter 5.2 - 7.4 mm (AWG gauges 1 - 4) or cross section 16 - 35 mm. Minimum wire size 16mm (5/8") Max. Wire clamp: 9.5mm/0.37", mini wire clamp: 6.5mm/0.25" Positive inner diameter: 17.5 ~ 19.1 mm, negative inner diameter: 15.9 ~ 17.5 mm. Easy to useWith positive and negative labels, easy to identify. 1 Allen key included for easy installation. Wide application: the battery clamps car connections can be used for cars, vans, caravans, motor homes, truck batteries, ship boats and machines.