After 6 months of use, the shower's phone got rusty and the battery switch remained in my hand

Very satisfied with the product (1 week of use) but also with the price as I found it in a 'supermarket' for 110€, just like the store where I bought it, which is strange because they were more interested in whether I received it on time and not the opposite... as usual.
After 1 month of use... due to the flat surface at the faucet area, it "holds" water, resulting in salt stains forming very quickly. So either immediate cleaning after showering or regular cleaning... damn it!