The PermaFLOW lets you use an external knob on the outside of the drain to move a wiper that clears out blockages and of course, you can see what's trapped down there through the transparent material. No need to pour chemicals down the sink or call a plumber. It also claims to prevent clog build-up as opposed to the traditional P-traps.
An additional interesting feature is the bypass option that allows water to flow through an upper chamber if there's a sudden buildup of debris.
The PermaFLOW is easy to install. You can retrofit a P-trap drain with the included adaptors that fit standard 1-1/2-inch (kitchen) and 1-1/4-inch (bath) plumbing.
PermaFLOW comes with a 10-year replacement warranty and is designed to work without problems with conventional drain chemicals.
(Please note prices are subject to change and the listed price is correct to the best of our knowledge at the time of posting)