The sand timer constantly stops, making it useless as a timer. My kid doesn't pay attention to it any more because he knows it jams. I've tried three now in case it was a faulty batch, but all have had the same issue.Great when it works. Doesn't work often.Really disappointed with this item! My son has had it for less then a week when the top (white tooth) fell off.... out slipped the inner tube and smashed as its made of glass. I don't think its sensible for it to be made from glass with it being for children.Waste of money as no longer can use it & left broken glass all in the sink!This exploded whilst my son was holding it! Luckily he wasn't hurt by any of the glass.Ordered one of these which arrived broken and smashed inside. Amazon replaced so happy days. Second one arrived and my boys loved it. All was working well. They used it for brushing their teeth and making sure they did a good job. As they are 3 and 5 it inevitably got dropped. It completely smashed inside rendering it useless. Therefore don't buy this if it is for children to use. Only saving grace is that only the inside smashed so the glass was contained. Absolutely useless product not fit for purpose.