Boating Essentials - Marine Battery Terminal Kit - BE-EL-51006-DP Marine battery terminal kit from T-H Marine. Convert your automotive post-style battery to a marine wing nut-style battery with this color-coded marine battery terminal kit. Color-Coded Marine Battery Terminal Kit Battery Negative Post - 5/16" Battery Positive Post - 3/8" 12V Marine Convert your Automotive Post Style to a Marine Wing Nut Style Battery