One of the most rugged, heavy-duty alarms on the market. These alarms are designed to withstand the most punishing environments. They have #8-32 UNC terminal studs on the back of the unit. Used by major OEMs. OEM design housing mounts on 6” (152 mm) centers. Weight: 2 lbs. 4 oz. (1.02 kg) The self-adjusting alarm model automatically adjusts to 10 decibels above the surrounding noise.