"I bought this to build Technic RC cars (which are awesome). It works with my Amazon Basics rechargable AA batteries and last for many hours of driving, much longer than I thought. So long, that I wish there was a AAA battery pack designed to work with Technic. When I go to build this into our creations, I always find the pin holes are not where I want them. I wish there where holes oriented in all three axis. I also wish the pin holes where near the corners of the battery box. There is a lot of room for improvement on this design, including making it less awkward to mount and perhaps more compact."