Vinnic L1325, RFA-18, A28PX, 4LR44, A544, PX28A, 4G13 6V Alkaline Battery for Dog Collars and Barking Control Systems - GN Batteries & Electronics Inc.
GP 476A High Voltage 6v Alkaline Battery in Reference to 4LR44, 476A, A544, V4034PX and PX28A - Walmart.com
Amazon.com: 10 Energizer 4LR44 6 Volt Batteries : Health & Household
Vinnic 4LR44 L1325 476A 6V High Voltage Alkaline Battery 5 pcs. - TheBatterySupplier.Com
Amazon.com: Energizer 4LR44 Alkaline Battery - Energizer 4LR44 Battery 6V; 92MAH; 13X25mm Alkaline for Burglar Alarms etc. (PX28) (A544) (4G13) : Health & Household