Amazon.com: Synergy Digital Dog Collar Batteries, Compatible with HQRP CPU Dog Collar, (Ni-MH, 4.8V, 400 mAh) Ultra High Capacity, Replacement for GP 28AAAM4SMX, Battery, Combo-Pack Includes: 3 x DC-1 Batteries : Pet
Dogtra 1202NC Dog Collar Battery (Ni-MH, 4.8V, 400 mAh) Battery - Replacement for GP - 28AAAM4SMX, GP - 40AAAM4SMX, Mighty Pets - BP-12, Sanik - 4SN-2/3AAA40H-H-XA1, Interstate - NIC0962 Batteries - Walmart.com
Ni-CD AA 400mAh 4.8V Ni-CD Battery Pack Replacement for Emergency / Ex – Batteryhawk, LLC
Amazon.com: Synergy Digital Replacement Battery, Works with GP 40AAAM4SMX Replacement, (Ni-MH, 4.8V, 400 mAh) Ultra Hi-Capacity Battery : Electronics
Amazon.com: GP 40AAAM4SMX Replacement Battery Combo-Pack Includes: 2 x SDDC-H1102 Batteries : Health & Household
Replacement Battery for Dogtra Receivers & Transmitters - Battery Warehouse