7" immersion heater thermostat

A request to all engineers reading...

Does anyone know of a really high quality 7" immersion heater thermostat? A few years ago, someone in the trade pointed me towards a 7" thermostat which was so high quality, it didn't need a thermal trip! I know that since 2004, they have needed one, but sure enough, I Googled it at the time and managed to order it online. It was very expensive, but the customer was happy. I need three of them, now. I have tried to find it, but no luck. Any ideas, anyone? Cheers, Barry.