Power Pet Energy Saver Series, patio pet doors combine the most advanced pet door made with the highest quality aluminum sliding glass insert. The unit can be adjusted to fit into your sliding glass patio door frame instantly. The extra rigid, deluxe aluminum extra frame houses a dual pane, Low E glass panel for superior energy efficiency. The fully automatic, pet operated Power Pet door mounted below the glass panel is a motorized unit with a air-tight, panel that allows your pet to come and go without human assistance. You get an attractive, high quality, product that increases the security and energy efficiency of your home. Best of all, no more doggie doorman duty. Large 12.25 in. x 16 in. opening for cats and dogs up to 100 lbs. Dual range controls let you set independent inside and outside activation distances with directional sensing system that opens the door only when your pet is approaching. 3 power modes include standard AC wall adapter (included), auto-recharging battery backup (battery backup included) and battery only (optional charger kit sold separately). 4-way control with in-only, out-only, full-access or closed-and-locked options lets you set your pet's level of accessibility. Completely safe for pets and small children. Secure against animal and human intruders with an automatic dead-bolt locking system. Additional locking bolt enables you to secure your patio door to the pet door insert. Ultrasonic waterproof collar (one included) will not interfere with or be affected by other electronic devices. Additional automatic safety retract system raises the pet panel if it encounters an obstruction during closure. Uses unique gravity closure system safely that lowers the panel by its own weight, not by using the motor. Additional collars can be purchased from HiTech Pets or on the Home Depot website.