The batteries I bought from Battery Junction came with solder tabs attached at each end of the battery. All I had to do was solder the wire to the tab and in turn, the plug which is a standard size "N" power plug. The inside contact of the plug is positive and outside jacket is negative. My neighbor is an electrical engineer and he looked at the voltages and said it wouldn't make any differences and should be well within tolerances of the Airshield. In fact we measured the voltages of a fully charged OEM cell (= 2.98v) vs the replacement cells (= 3.71v) prior to running them in the unit for the test of run time. I found it interesting that even with a full charge the new OEM batteries didn't even reach the operating voltage for the unit.
