These non orthogonal slots, when coupling to corresponding non orthogonal rails in the pocket of a battery charger, allow batteries of various sizes to be inserted into a single charger pocket with reliable and consistent electrical connections between the electrical contacts of the pocket and {HEAD ~ the charging terminals} of {TAIL ~ the battery} 
These non orthogonal slots , when coupling to corresponding non orthogonal rails in the pocket of a battery charger , allow batteries of various sizes to be inserted into a single charger pocket with reliable and consistent electrical connections between the electrical contacts of the pocket and { HEAD ~ the charging terminals } of { TAIL ~ the battery }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL