Universal Battery Box

This battery box works both for REV slim pack batteries, and Tetrix style batteries. The REV batteries set vertically, and the Tetrix batteries set horizontally.

http://www.revrobotics.com/rev-31-1302/
https://www.pitsco.com/TETRIX-12-Volt-Rechargeable-NiMH-Battery-Pack

It works great with Actobotics parts.