The Ut2500 Is A Simple To Use Universal Transmitter That Is Compatible With Our 2500 Series Products. The Ut2500 Operates On A 3 Volt Lithium Battery (included) And Has Several Different Methods Of Activation. The Ut2500 Has A Push Button That Can Be Used As A Panic Button Or A Wireless Doorbell. There Is Also A Magnetic Door/window Contact And Terminals For Both A Normally Open (n/o) And Normally Closed (n/c) Input. These Inputs Can Be Used With Any Sensor Contacts.