Fully functional, original tags, very clean. Mass flow sensor for air by Books Instrument, model 5861 i Series. Includes two stainless steel fittings. Flow rate: 55 SLPM. Gas: Air. Ref. temp 0°C. I/O signal: 0-5 Vdc. Power: 24 Vdc. P1/P2: 5/0 psig. 1500 psig max. Base is model 586li. Pre-owned and tested industrial surplus from a closing plant in Quebec, Canada. Minor surface scratches only.