The Hanwell 5000DP radio telemetry transmitter, designed for use with a Hanwell environmental monitoring system. The units are in IP65-rated cases and are suitable for use in tough environments. Utilising an integral temperature compensated pressure sensor the RL5405 differential pressure transmitter delivers exceptional performance. The sensor utilises silicon, micro machined, stress concentration enhanced structure to provide a very linear output to the measured pressure. The ports are designed with matched dead volumes. This series is intended for use with non-corrosive, noionic working fluids such as clean dry air, dry gases and the like.