Built-in sensor, no sensor cable required. Special waterproof design for diving. Comes with suction cups for direct access to the aquarium. Small size does not take up space, can be easily moved. Great for use in aquariums. It can also be used in other scenarios. 【Wide range of applications】Mini LCD digital thermometer hygrometer with probe is very popular and widely used in living room, greenhouse, musical instrument room, wine cellar, basement, bathroom, warehouse, attic, baby room and changing room.