A practical, small, easy to use battery puller.  Snaps on with a firm satisfying "CLICK" and easily slides off. Easy to hang on to, but small enough to clip on to your drone bag or keep in your pocket without losing it.  

Based off this model but re-imagined with a finger hole to enable someone to actually hang on to and use it:
https://www.thingiverse.com/thing:4824830

The STL and model are original, in that, they was completely drawn up from scratch based on the dimensions of the original. 

Looking for this on Printables? https://www.printables.com/model/1436461-f150-receiver-safety-chain-grommets