We got this vial for my husband, because he loved being able to see the level of the oil easily. However, the first day of having it, he dropped his keys as he was taking it out of his pocket, probably no more than 4 feet. The glass of the windows shattered, rendering the vial unusable. We purchased a replacement of the same style, thinking that he just needed to be more careful. He had this one for three days before he took it out of his pocket and found a crack in the glass of the window, just from standard wear-and-tear of having the keys in the pocket. The vial is a lovely one, and he really liked it, but the glass of it is just too fragile for day to day use. I would recommend it for people not planning to keep it with their keys, but if you plan to carry it around for regular use, it'll most likely break on you.