The XS01-W smoke detector only measures Ø 78 × 48 mm and has a sleek design that fits into any style of home. With advanced photoelectric sensing technology, this detector performs smoke concentration analysis to accurately and quickly alert you to any smoke. Up to 24 wireless detectors can be linked together using RF technology to create a smart security network for complete protection of your home. So, when one alarm sounds, all devices are triggered to alert everyone in the home of danger and to take action immediately. To quickly identify the source alarm, simply press the test/silence button on any one of the interconnected units.