it just needs to be broken in. The mount isolates it from vibration on the table and allows it to be positioned wherever its needed. In US size. i boutght these on impulse due to my crippling depression in hopes that something happy might come of it. Good arch support too for a slide. The plus side to it being a heavyweight is that it stays where you put it and is less prone to vibrate the surface it?s on. This discolouration is irreversible and appears to be connected to a gradual reduction in how springy the foam is. this is a good buy***READ UPDATE IF YOUR SAMSUNG KEEPS DISCONNECTING THESE *****I noticed that my samsung s21 keeps disconnecting these after a bit of inactivity. I had a dongle on my keys, lost it twice. It?s very soft and squishy on my knees (giving kids a bath) and the bottom is very good at gripping the floor, so it doesn?t slide.