Replace the battery in your PetSafe 100m or Basic Remote Trainer or older model of the Deluxe In-Ground Cat Fence. This 2-pack of 3-volt coin cell batteries has a 5-year shelf life and typically lasts 1-3 months. Features:- - Compatible with PetSafe Remote Trainers and older models of the Deluxe In-Ground Cat Fencesystem: - 100m Little Dog Remote Trainer (PDT20-10644) - 100m Big Dog Remote Trainer (PDT20-10645) - ST-100-LD Little Dog Remote Trainer (PDT17-13471, PDT45-13472) - ST-100-BD Big Dog Remote Trainer (PDT17-13473, PDT45-13474) - ST-70 70 m Basic Remote Trainer (PDT17-13480, PDT45-13481) - Deluxe In-Ground Cat Fence (model purchased before August 2010, PCF-1000-20) - Deluxe In-Ground Cat Fence Extra Receiver Collar (model purchased before August 2010, PCF-275-19)