Compex Battery Pack for Edge, Performance, Sport Elite Muscle Stimulators - Rechargable, Ni-MH, 4.8 Volts Compatible with the Compex Sport Elite, Performance and Edge Muscle Stimulators Compact and lightweight for daily use Battery Type: 4h-AA1500; nickelmetal, Ni-MH Volts: 4.8 Dimensions: 60 x 60 x 14mm