This is a box designed to hold a large 3-cell lithium-polymer battery (11.1v) and at present has two cutouts for a 3-pin Molex fan power connector and banana jacks. The box has a curved protrusion on one end for batteries that have wires coming out of the end instead of straight out (or have a bump from large wires). The top portion is secured by means of several small screws.Battery area size: 148x51x36mm Depending on the battery used, you could use higher cell packs (for higher voltage) in lieu of milliamp-hour capacity if desired.