This is a replacement mount / dock for a 36v 5.4Ah waterbottle battery for the new 2020 Sprinter kits and beyond. Controller and dock only. Controller is built into the base of the dock in a clever and waterproof case. A replacement water bottle battery is available here.
For Hilltopper kits made prior to 2020 please see the universal replacement battery or contact firstname.lastname@example.org with your model and estimated year for replacement battery options (for old 24v kits see our DIY battery module hack for one clever and thrifty option).