Review on 🚗 Universal Vehicle Cup Holder Mount Adapter with 3.5” 90mm Suction Mount Surface and Adjustable Base for Standard GPS Mounts & More - Holds Smartphones (iPhone, Galaxy S21), Tablets, Radar Detectors, MP3 Players, and More (Compatible with Existing Suction Mounts) - Includes Free ChargerCity Micro SD Card Reader by Janet Tijerina

I could give 5 stars but the problem is the surface doesn't vacuum for more than a few minutes. This has been tested with at least (4) different device suction cups, all of which came out in 5 minutes or less. I was able to use mirror tape on the underside of the suction cup which made for a permanent hold, but if you're selling to use a suction cup it should last quite a while! All of the suction cups on the devices I tested stayed on the clean glass for as long as I left them on. I think the solution would be to just make the mounting surface much smoother.