TRV4 Classic chrome/white control knob with chrome plated brass body that can be fitted on the flow or return with sensing head in either a vertical or horizontal position. Liquid filled sensor with frost protection, range limiting and balancing facilities. ½" BSP TM radiator tailpiece. TRV4 approved to EN 215. Lockshield valve (L/S) approved to BS 2767-10.

NOTE: the TRV4 sensor head IS NOT suitable for use with the TRV3 body.