Product review (3 stars): Overall good product but had to tweak a bit to be useful
I purchased this kit to install a in-line filter outside of my refrigerator with an ice maker, so just used the 1/4" waterline, compression sleeves and inserts as well as the 1/4" connector. The compression insert is plastic and the one I received (two of them) didn't hold the pipe inside the compression nut so it would slip out upon moving the tube... tried to tighten but just wouldn't work.
I purchased the brass insert instead at Home Depot ($1.64 with compression sleeve) and replaced with it, and that made the compression nut to hold the tube. Not sure if the plastic ones were defective or just didn't do the intended job...
Overall, a cost effective kit that supplies necessary items.
Always REMEMBER to use a new compression sleeve once you've tighten the nut, or it will leak (don't reuse) and if the water line is a plastic one, never use the copper sleeve.