Trolmaster Hydro-X's optional smoke detector (MBS-SD) can alert the user of smoke in the grow area at any time. Up to 5 smoke detectors can be connected to one Hydro-X control unit. Once a smoke detector detects smoke, the user will receive a notification on their phone to detect potential problems early. The sensors should be kept dry and clean to avoid failures. The package includes 1 smoke detector (MBS-SD), 1 16ft RJ12 cable and 1 RJ12 T-adapter. Technical specifications: Dimensions: 160x86x86 mm, Weight: 0.37 kg.