... dryer,hand/foot warmer,massager,physical therapy heater. 1) Aluminum shell. PTC heater is very appropriate under 260 temperature. ... Main appliances: hair straightener, hair crimper, wax melting heater, humidifier, water boiler, liquid warmer, coffee warmer, polymer ... Ceramic shell. It is very appropriate for low power amd 50~250, Main appliances: mosquito destroyer, aroma emanater, massager ...