A programmable key for use in a security system for protecting items of merchandise has a housing, a power supply mounted in the housing, a logic control circuit which includes a controller, a wireless communication circuit and a security disarm code (SDC) memory. The key has visual indicators such as an LED which is operatively connected to the logic control circuit and pulsed to indicate the state of the SDC. The control circuit includes a timer which has a preset time limit programmed therein, which invalidates the stored SDC if not refreshed by a remote programming source within a certain time period. The logic circuit further includes a counter which counts the number of activations of a control switch, and which permanently deactivates the control circuit upon reaching a certain count value to ensure that the internal battery has sufficient power to maintain the key operational. The wireless communication circuit preferably is infrared (IR) or radio frequency (RF) controlled.