Invisible Fence Battery Compatible Compare to Invisible Fence Batteries R21 Battery R22 Battery R51 Battery Compatible with Invisible Fence Power Cap Microlite Receiver Collars NEW and IMPROVED YUUGE SAVINGS OVER OEM INVISIBLE FENCE BRAND BATTERY SETS! - Why spend more money to keep your pet safe? Save cash over high-priced OEM batteries with these dog collar batteries from Eco Extreme. Contains 4 high performance replacement batteries that are 100% compatible with Invisible Fence brand R21 battery, R22 battery and R51 battery Microlite receiver collars. KEEP YOUR PET SAFE & SECURE - Your dog deserves only the best - dont waste time and money with cheap knock-off batteries that lack charge or can potentially malfunction. Make the safe choice with the Eco Extreme invisible fence battery replacement power pack. HASSLE FREE INSTALLATION, ECO-FRIENDLY DESIGN - Each of these ultra-lightweight, high-density batteries comes fully charged and ready to use. Whats more, youll be helping to keep the environment safe with this eco-friendly choice. BUILT TO LAST - These backup batteries feature a high-density, 3-volt lithium ion core that is built tough enough to withstand the rough and tumble activity of your pet. 100% GUARANTEED INVISIBLE FENCE BATTERY COMPATIBLE  NO HASSLE GUARANTEE - Warranted by the manufacturer to be a perfect fit for all Invisible Fence brand R21|R22|R51|Microlite receiver collars and replaces Perimeter battery R21. What are you waiting for? ORDER YOURS TODAY!