Side plate for mounting the Thundershot transmission to a Grasshopper 2 / Super Hornet / Riding Fighter tub. You need 2 of these, and you will need to use the 2.5mm holes as drill guides to drill 2.5mm holes through the tub, then use Tamiya 3mm self tapping screws to hold it all in place. You can read more here:
https://www.tamiyaclub.com/forum/index.php?/topic/85012-grasshopper-2-ultra-g-independent-suspension-all-round/&do=findComment&comment=958337
You also need the "Ultra G Side Plate Spacers" parts which are also on the store.