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 15 G of force for the PC680 yet only weighs .275Kg or 10oz. This unique design allows for simple, easy installation with the dimensions: 7.1″ L x 3.1″ W x 6.5-6.6″ (adjustable)H or (180mm x 80mm 166-168mm).