The Listen Tech Rechargeable AA NiMH Batteries (2) LA-362 do not suffer from memory conditions (as do nickel cadmium batteries), therefore they fully recharge hundreds of times. This provides many years of dependable service on one set of batteries. Two (2) AA batteries are required to operate each Listen belt pack device, and eight (8) are required for the LR-600. Each LA-362 pack includes two (2) batteries. Use with Listen drop-in charging cases.