The HMX4 series of Gefran, are pressure transmitters for using in High temperature environment and specifically designed for melt pressure measurement and available only to be used in large-scale fixed installations or in large-scale stationary industrial tools, typically extruders, or for laboratory B2B equipment for R&D purposes according to the European Directive 2011/65/EU (see informative note RoHS II). The HMX4 series of Gefran are flanged 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 strain-gauge technology. The SIL2 and PL d approvals make the product suitable for use in the Functional Safety applications, particularly in the process plants for the production of polymers, where it is an essential requirement.