This part in conjunction with the bottom cup allows you to install closed ends on your Tamiya Thundershot, Thunder Dragon, Terra Scorcher or Fire Dragon. Still requies the use of a stick pack battery. Does not fit square Lipo. Useful for tracks where enclosed batteries are a safety requirement.
The usual 3D printed product preparation applies here. You may need to run an exact knife around the recesses to get a good fit on the chassis. Clean out the small holes with a 3.1mm drill. Clean out the large holes with a 6mm drill.
To install, remove the kit battery retainer, and place the slots on the underside of this part over the retainer bosses. I would reuse the self tapping screws from the kit to screw into the holes you were using for the original retainer and either add another set of self tappers to the other pair of holes or tap and use two M3 x 8 cap head screws.
You need two per buggy for a complete set. Use in conjunction with the battery holder cup
https://www.shapeways.com/product/LJEC2TTPG/thundershot-chassis-enclosed-battery-holder?li=shareProduct