Tested, very clean, includes its original HMT337 probe with a sintered filter and user's guide (209 pages pdf). Unit is a Vaisala HMT337 Dewpoint & Temperature/Humidity transmitter, connects to external digital display. A Power-1 supply (120VAC to 24VDC) can easily be added inside (not included). High quality unit, made in Finland. Industrial surplus from a closing plant in Montreal (Quebec, Canada). Minor surface scratches only. The HMT337 probe included is for demanding processes, with an optionally warmed and vapor tight probe head.