3/8″-16 Terminal Adapter: For use with our red 12v S9 starter batteries and with deep cycle batteries with 3/8th terminals on them. SAE 3/8″-16 thread female, used for any battery that has the terminal 3/8″ threaded studs (lead-acid or lithium batteries) extension to standard top post. Sturdy terminal post adapter for increased strength, conductive and reduced corrosion. Adapters come as a set – one positive and one negative. Weight – .2 oz