High Accuracy:The fish tank thermometer has a temperature range of 0-60 for different water temperatures. It has a built-in copper nickel-plated temperature probe, which is precise and sensitive and can sense every 0.1 change. LED Digital Display:Designed with LED digital screen and large green font display, it is easy to read the data day or night. Touch the button to display the temperature and go to sleep after 5 seconds. Mini and Compact:The thermometer is mini and compact, as thin as about 12mm/0.47inch, which fits more closely to the tank wall and prevents dropping.A type is about 4343mm/1.691.69inch (LW), B type is about 48mm/1.89inch (diameter). Long lasting battery operated:The thermometer outside the fish tank has a built-in 3V button battery with ultra-low power consumption and can standby for about 5 years, durable. Suitable for outside the fish tank:This thermometer is designed for outside the fish tank, just stick it directly. It is cordless, avoiding the hassle of tangled wires, making it more convenient and safer to use.