You set the water temperature where you want it. You turn it off and on immediately and the water comes out cold. Then you set it again to the correct temperature. You turn it off and on immediately and the water comes out hot. There is some manufacturing problem.

A simple battery, nothing special.
The 2 stars are for the non-existent 5-year warranty and the complete indifference of Viospiral!!!
I bought it from a local plumbing store 2.5 years ago.
After 2 years, the internal "embedded" iron nut (not even copper) in the flow distributor knob came off.
A month ago, I sent an email to Viospiral with photos and asked them if the 5-year warranty is valid or at least if they have a replacement knob so I can buy it.
For a whole month, they haven't even bothered to reply!
(If they tell me that my individual email went to the Spam folder, that's a cheap excuse.)

Brass body and mechanism with a 5-year factory warranty, for its price it is more than good

Purchased in early August and installed by a plumber. The mixed temperature is normal (with slight adjustments, the temperature is set without gaps) and it doesn't make noise. It seems normal for its price (typical spiral and phone, etc.) and time will tell if it will have issues. If I notice anything, I will update the review (5/5 now because there is nothing negative). In the photos, I included what was in the box.

It seems to be of good quality. It is generally quite lightweight compared to a 15-year-old one that I replaced. I don't think it will last that long, but it has a 5-year warranty. The shower head and the bracket seem very fake. Other than that, it is complete with rosettes, rubber bands, and even S threads to reduce the distance between hot and cold. Very satisfied