This external sensor is an optional accessorie for Heat-it thermostats.
Module for installation on DIN rail, Z-Wave + technology for the control of hydraulic heating up to 10 outputs. Heatit Z-Water is a DIN rail mounted controller for controlling hydronic heating.
The Heatit Z-Smoke is a multifunctional wireless smoke detector for Z-Wave based smart home systems. Version powered by AC mains (230VAC). It also offers smoke detection, a presence sensor, a temperature sensor and emergency lighting. We can say that it is a 3-in-1 sensor.
Heatit Z-Temp2 is a battery powered, surface mounted (non-flush) temperature thermostat designed for use with hot water based heating systems. It does not have a maneuvering relay.
Heatit Z-TRM3 is an electronic Z-Wave wireless technology thermostat for electric underfloor heating, designed to be mounted in a standard wallbox.