This is a set of holding rings designed to hold a Coconut Shell based Activated Carbon Water Filter. The inner diameter is for a 50mm filter housing. You can easily install it inside the sink cabinet along your water hose. I am using an 8mm water hose to supply water to my cooler. Same one may be used for refrigerators, etc. In addition, I designed a holding clamp for the 8mm plastic hose, so you can clamp the hose to cabinet walls using screws while you bring the hose to the place where the filter is attached.

Holes of the edges of the Filter holder rings are in purpose of tightening the filter with tie bands in case the filter is a little smaller that 50mm. I believe the only way to install and remove the filter will be by sliding it from a side and not by clicking it in, as the ring walls are pretty thick and may not open up enough under light pressure and get damaged if pressed too much. So keep in mind leaving enough place for sliding the filter out.