Designed to insulate integral marine wing nut terminals protecting battery cables from corrosion and shorting. Constructed of injection molded PVC. Satisfy USCG and ABYC requirements for the prevention of accidental grounding of battery terminals. Color coded to avoid polarity misidentification. Will fit most marine batteries as well as automotive batteries using add on marine terminals. Cable Size 4, 2, 1 A 1/2" B 1-5/8" C 1-11/16" D 2-7/8" Color Red