Camco RV Large Battery Box is a black lightweight, heavy-duty corrosion-resistant polypropylene box which is designed to secure and protect your battery. It includes lift-off lid, durable woven hold-down strap, foot clamps and stainless steel screws. This box meets USCG CFR 183. 420 and ABYC E-010. 7 specifications. It fits group size 27, 30, and 31 batteries with inside dimensions measuring 7 ¼” Wide X 13 ¼” Long X 8 5/8” tall with 2” additional head room for battery terminals.