The Waterdrop under-the-sink is a slick device. The installation is simple, and the cartridges make it a breeze. I will warn you, however, that the filter won't produce anything more than a dribble of water (and the company will blame your installation and your water supply even though absolutely nothing has changed in your home) UNLESS YOU REPLACE BOTH FILTERS AT THE SAME TIME. This is expensive and silly because one has a longer life span. Horrific customer service with no assistance given to this issue whatsoever, and we have had the Waterdrop unit for several years and have been through this with them every time we change a filter. Replacing them both at once is the only way you can actually get decent water flow out of their spigot.