IP64 is a rating for everyday use; meaning it is splash resistant.
Therefore splashes of water from a sink or rain will not be a problem, but it cannot be guaranteed for use while submersed in water.
The unit itself can be submersed in cold or hot water for a short time without water entering the unit. But if for example it was in hot water of 60℃ and then moved to cold water of 0℃, the internal pressure of the logger would drop and water may seep into the case.
If you wish to measure and record the temperature in water, please place only the sensor in the water.
RTR-502/502L, TR-52, TR-52S, TR-52i
September 02, 2016