The Tyco 811HExn 516.800.536 is an intrinsically safe (I.S.) heat detector that is part of the Tyco 800Ex-series. The Tyco 811HExn is used with the Tyco MUBEX base.
The mode of 811HExn may be:
EN54-5 A1R, rate-of- rise normal ambient
EN54-5 A2S, fixed 60°C
EN54-5 CR, rate-of-rise high ambient