If you are using a Honeywell 5821 Temperature sensor and you have an area where you can't exactly put it because of fear of low temperatures damaging the unit then you can use this. The Honeywell T280R is an extension probe for the 5821 and allows you to monitor a freezer or refrigerator. Very handy for restaurant uses!!
Specifications:Chemical Properties: Non-corrosive Waterproof Max. Compression Force Applied To Probe: 10 lb. force Max. Tensile Force Applied Between Probe and Cable: 5 lb. force Max. Cable Length: 300 Feet. The T280R may be extended from 15' up to 300' using shielded 24 AWG cable.