The instruction manual is in the last few pictures, if you need detailed electronic documents, please contact us 2 Working modes: this digital LED temperature controller module has 2 working modes, heating mode ( temperature is lower than stop temperature) and cooling mode ( temperature is higher than stop temperature), range from -50C to 120C; The high temperature control accuracy reaches 0.1.Stable and : the LED indicator light can display the current output status; The digital display tube can display the measured temperature, and the temperature measurement and control accuracy is high. Waterproof probe: equipped with a 1-meter NTC10K probe made of stainless steel, which is waterproof and not easy to rust, easy to use and can last for a long time Durable material: this XH-W3230 digital thermostat switch is made of plastic, one of the major synthetic resins, which is non-toxic, strong impact resistance, heat and low temperature resistance Suitable for: the temperature controller module can be widely applied in the conditioning , incubators, equipment cases, temperature control protection and others Colour:black Material:plastic type:24V Package Contents: 2 x temperature controller Only the above package content, other are not included. Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.