Injection molded polypropylene plastic boxes effectively collect battery electrolyte, allow ventilation, and prevent accidental contact of ungrounded battery terminals. Patented Snap-Top™ lid secures the lid to the base, heavy-duty handles resist cracking, and vent hole cover plugs limit water entry. . Fits 12 Volt batteries. Medium box fits Group 27 batteries. Dimension: Inside (13.38”L x 7.75”W x 10.00”H), Outside (16.00”L x 9.25”W x 10.25”H)