EVEN IF ARRIVED DEFECTIVE, THIS PRODUCT CANNOT BE RETURN.
I purchased this to upgrade from the WP-100. The WP-662 is not found in stores locally, at least not for me. Unfortunately it wasn't an upgrade, but more of a downgrade. My product must of been defective, because the pressure was very low compared to the WP-100. For example, I was on pressure 8 with this product, while with the WP-100 I was on pressure 4 to obtain the exact same pressure. That means this product was 2x weaker. I don't recommend going on the highest setting, but the pressure was so weak it was the equivalent of rinsing your mouth with water. That is not strong enough to get rid of plaque whatsoever and you were able to feel it. Also the pressure kept getting cut off occasionally.
Aside from the possibility of my product being defect, this product can only store 2 tips, meanwhile the WP-100 can store up to 4 and even more if you stack them on top of each other. The storage for this product is on the side of the water storage and it's actually hard to get your tip from there, unlike the WP-100. The only thing this does better than the WP-100 is that it looks better and you can turn the flosser off and on with a switch. There is also a massage setting which the WP-100 doesn't have. However that setting is useless and you'll most likely not even bother using it.
So basically if you want the best flosser, go with the WP-100. Don't waste your time with this product. The WP-100 has a button you have to press to cut off the water which is terrible, but at least the flosser does what it's supposed to do, unlike this one.