XUELILI Smart Immersion Heater Timer Switch, 2.4Ghz WiFi Water Heater Switch, Smart Wall Touch Boiler Switch with Timer Works with Alexa, Google Home, IFTTT and Smart Life APP, White, 20A, 4400W :
Amazon.co.uk: Economy 7 Immersion Timer
Amazon.co.uk: Immersion Heater Timer
SPARES2GO Energy Saving 15 Minute to 2 Hour Electronic Boost Timer for Immersion / Room Heater : Amazon.co.uk: DIY & Tools
Lowenergie Digital Water Immersion Heater Timer, 7 Day programmable, (16A) : Amazon.co.uk: DIY & Tools