Electric showers: A guide to pressure relief devices (PRDs). - YouTube
Pressure Relief Device for Triton,AIEVE 2-Pack Pressure Relief Device PRD Inc Rubber Ball and O Ring Valve Shower Parts Compatible with Triton Electric Showers (Replace of 82800450) : Amazon.co.uk: DIY & Tools
SPARES2GO Pressure Relief Device for TRITON Electric Shower PRD + Seal Burst Disc x 7 | DIY at B&Q
Pressure Relief Device for Triton,AIEVE 2-Pack Pressure Relief Device PRD Inc Rubber Ball and O Ring Valve Shower Parts Compatible with Triton Electric Showers (Replace of 82800450) : Amazon.co.uk: DIY & Tools
Solenoid Coil Pressure Relief Device for TRITON Electric Shower PRD Seal Kit | eBay