As a rule of thumb, if your water supply is normal water also known as fresh/ soft water, you can pretty much use any model of instant shower that pleases you; without worrying about damaging the heating element.
KShs 3,400
This product has multiple variants. The options may be chosen on the product page
Discontinued
With normal/ fresh/ soft water, you can use any instant shower/ heater without worrying about the element. With proper installation/ use, a good quality instant shower will serve you for a very long time.