They may indeed be different and perform a bit different.... but the reason I think they ARE the same is that Maxamps got a shipment of 4000s that were the wrong dimensions... a mistake from the manufacturer. Guess what the dimensions were? Exactly the same as Truerc's 4000s
This doesn't imply that they must be identical, but it looks like a duck to me...
speaking of these mistake cells... I need to check and see if Austin has any left.... to fix up my packs.
I hvae bought form both Dan and Austin, both are great guys imo.