Product review (3 stars): Inconsistent Quality
When I first received this the small white ring would not fit over the grey tube at all.  After contacting the seller they promptly sent me another set and the white ring was correctly on the tube.  After getting this resolved the install was straight forward.

After install be sure to test the water flow to make sure it is at a fast drip.  Even though the directions say to run your water valve completely open, some homes will have too high of water pressure and push more water through the tube than needed.