Few people buying the hand-watch seem to pay their attention to the watch-glass and the material it has been made of. However, this element is quite important because of the functions it performs such as protection of the watch movement and the aesthetic outlook of the hand-watch.
Perhaps you have observed a scale that is located along the rim of a modern hand-watches. This scale is a Tachymeter. You can recognize it by title “Tachymeter” and also by the marks “60” being opposite to the mark “12 hours” and “120” opposite to the mark “6 hours”.
Do you remember that feeling when you take on a new hand-watch? You may feel its weight with every move of your hand and even without it, when a watchband slips on a skin torture you with a question: when will I get used to it as I did to the old one?