With the universal MR33 steel battery weight you can get the balance in your car close to perfection while lowering the center of gravity at the same moment. Only 0.6mm thick and has a total weight of 28g. It will fit perfectly under any standard size 2S lipo pack and is a great setup option if you use very light packs between 220 and 260g in your car.
Shorty version weighs 20g at .6mm thick.