If you are using the battery box for the EarthX Lithium batteries, you will use a foam spacer on the left and right side of the battery for a snug fit. If you are using the battery box for the PC680, you will use the foam spacer on the backside at the bottom of the case to adjust for the tapering of the case for a snug fit.
This battery box was engineered to be strong enough to withstand 30 G of force for the EarthX Lithium Batteries or 6G of upward force and 9G of downward force with the PC680. It only weighs .23Kg or 8oz. This unique design allows for simple, easy installation with the dimensions: 7.1″ L x 3.1″ W x 6.5-6.6″ (adjustable height) or (180mm x 80mm 166-168mm).