Triton 83312810 Thermostatic Cartridge Service Kit
https://www.divapor.com/spares/showers/thermostatic-cartridge/triton-83312810-thermostatic-cartridge-service-kit-for-dart-3-amala-aisha-alpha-bea-mersey-bellisimo-camastra-favara-mana-verne-sentiment.php
Tips: This genuine Triton 83312810 thermostatic cartridge service kit is held in the shower valve with a retaining nut. Retaining nuts can sometimes be hard to remove because of mineral calcification. There are ways to loosen the calcification and take the thermostatic cartridge out. 1. Use a loosening agent such as WD-40. 2. Tap the spanner using a hammer (or a mallet) as you turn the retaining nut anti-clockwise. 3. Point a hairdryer on hot setting on the retaining nut. The heat will cause the nut to expand, and hopefully, it will loosen.
Please check out the link above for the complete list of compatible shower valves.