Check the listing for details. System Sensor 4WTA-B Photo Detector w/ Thermal Sensor and Sounder. Condition: New. Listed at 99.00 USD. Installation ease. Throughout the i3 series, installation is simple with its installer-friendly base and plug-in design. The base accommodates a broad range of back box and direct mounting options and provides ample space for pre-wiring the device. To complete the installation, the i3 detector plugs into its base with a simple Stop-Drop ’N Lock action. Intelligence. To reduce the likelihood of nuisance alarms, all i3 detectors are equipped with both drift compensation and smoothing algorithms. These capabilities minimize both short- and long-term causes of nuisance alarms, such as RF interference and dust accumulation. When connected to the 2W-MOD2 loop test/ maintenance module or an i3 Ready™ panel, 2‑wire i3 detectors can generate a remote maintenance signal when in a maintenance or freeze trouble condition.