Premier Plants Analog Aquarium Glass Thermometer For Fish Tank Water Thermometer Reptile Terrarium Temperature Pointer Needle Thermometer ( CS-010) Maintaining the correct water temperature in your aquarium can be the difference between success and failure. And while heaters are great for regulating your tank's temperature, their readouts aren't always 100% accurate. Having a precise aquarium thermometer can help you track and adjust your tank's temperature accordingly. Each Floating Aquarium Thermometer comes with an optional suction cup, which allows you to place it alongside the tank’s walls for even easier access for a temperature reading. The suction cup mount is removable, and the thermometer should float on its own. Excellent large display of analog needle with a high accuracy of temprature with a great clea dispaly for inidication which is fully submersible into the water.