Ranks among the poorest quality products that I have ever had the misfortune to purchase. The water jet power is marginal. It is very difficult to insert or remove the water jet tips and became more difficult with use. The knobs are difficult to turn and don't operate smoothly. I almost returned it shortly after purchase, but made the mistake of keeping it for several months before throwing it out and replacing it with a Waterpik product that is much better in every respect and well worth somewhat higher price.