DAIWA WATER TEMPERATURE CHECKERNon contact water temperature checker Waterproof. Weight: about 21g Size Outer diameter 18mm* length 83mm Battery life: about 30 hours Water temperature is an important factor when catching fish. However, it is actually a tedious task to measure the water temperature due to the critical condition on rocks. This device is non contact type, so it can be measured with one push without touching the object. This makes collecting fishing data more easily