This Steering Wheel Alarm can effectively prevent potential car theft. It is equipped with four theft-deterrent features: warning LED, flashing strobe light, 120 db siren and hard steel lock. This alarm perfectly fits the steering wheel and with the wireless setup that takes less than 10 seconds- no expensive installation is needed. Three keys are included for unlocking the alarm. You can program your own IR code with the 6-digit programmable switches. The alarm will sound and LED will flash for a 30 second cycle when disturbed by window tapping or other significant jolt and will reset if no other disturbance. If disturbance continues the alarm will continue for another 30 seconds until the disturbance ends or the alarm unit is disarmed. The alarm unit requires two (2) 9V batteries that are not included. The IR remote requires 1 12V battery that is included. The alarm measures 14.5 x 7.75 x 2.75 inches