What is a ChickenGuard? New features include: Automatic door calibration to make the installation process as simple as possible; Automatic stop feature which protects your chickens from getting trapped as the door lowers and also prevents the string from getting tangled if there is an obstruction; Choose from 4XAA Alkaline batteries or DC power (9V to 12V – cables not included*). Battery warning light visible from 100 meters away. Backup lithium cell battery (CR1220 Lithium cell battery not included) that will keep the clock working when the batteries run our or while replacing them; New self-diagnosis capability with an alert message appearing on the screen until the required action has been taken. An integrated LCD screen ensures it is easy to set up and alter timings when necessary. You won’t need an 8 year old to program this door! And we have even designed extra big buttons so you can program the unit with your gloves on in the winter.