The HMF series of Gefran are pressure transmitters with HART communication protocol for using in high temperature environment with explosive atmosphere presence. The main characteristic of this series is the capability to read temperature of the media up to 400°C. The constructive principle is based on the hydraulic trasmission of the pressure. The fluid-filled system assures the temperature stability. The physical measure is transformed in a electrical measure by means of straingauge technology. The transmitters have been designed and manufactured according to FM standards with the following types of protection and features: - Explosion-proof (XP) for Class I, Division 1, Groups A, B, C and D - Dust proof (DIP) for Classes II, III, Division 1, Groups E, F and G - Indoor and outdoor areas classified as hazardous: Type 4X, IP67 - Rated ambient temperature of T5 Ta = -20°C to +85°C, T6 Ta = -20°C to +60°C