EM21 and EM22 sensors are IP67 waterproof rated, meaning they are safe for splashes, mist, and dust exposure. They are not designed for prolonged submersion. If you wish to monitor temperatures of liquids, use the EM22, which has an external probe to measure the liquid temperatures.
EM11 and EM12 sensors can be made water resistant with the addition of a silicone cover. To learn more, contact your Account Manager.