https://www.extremedogfence.com/shop/pet-accessories/batteries/battery-for-extreme-hyper-collar/ extremedogfence.com

Improve your beloved pet’s quality of life with the freedom to play, use the bathroom, or just get a fresh breath of air whenever he/she feels the desire
Magnetic sealing flap creates a barrier that separates the weather outside from the temperature inside
Includes a sliding security panel that is easily secured into place with 2 easy-slide locks. Keeps your house safe when you are away
Rugged construction. The tough aluminum frame will not deteriorate in eXtreme weather. The beauty and reliability of this pet door will remain year after year after year