Review on Mace Slimline Wireless Window Sensor by Grant Nordstrom

I have bought 4 more of these units to fit my Mace 80355 security system (they work) but they work very well. The thin line fits perfectly in our windows. The smaller block can be placed next to or above the larger block (L shape). This makes installation very easy. CONS: Units work well but half of the time the batteries are dead on arrival resulting in the additional cost of buying new batteries.