Review on 180 Piece Rubber Grommet Assortment by InstallGear by James Holker

Not much to say about them other than they work as expected and come in a variety of sizes. I use them to protect the wires going to the body of the Arduino project. This is plastic for prototyping, but metal will be used in the final versions. They are not suitable for waterproof applications without additional filler, but do a good job of reducing wire abrasion on the case. The installation is quite easy. I use a reamer to clean up the drilled hole and (sometimes) use some hot glue if there's too much play. Smaller sizes can be a little tricky. This is a compromise between easy installation and a snug fit once installed, but I prefer easy installation. In addition, this is a fairly common product that meets my expectations.