It revolves mostly around the metal tabs on the bottom of the radio. As mentioned above, the QC on these radios was just not there, so they varied wildly from radio to radio on the battery fitment. If the tabs are off, the batteries can get stuck or won't latch properly. We would have to bend (more like "tweak") them in or out to "calibrate" them to fit the various batteries that we use. Just be VERY careful when tweaking them as they do not bend very far at all before they break off. Out of the 100's that I tweaked, I only broke two. It takes very little movement to notice an improvement. Our reason for tweaking was due to the batteries getting stuck, which would occur when a user dropped their radio, bending the tabs. We had a method to remove stuck batteries that was non-destructive, but end-users would typically destroy the batteries, trying to remove them.