5 Pack Rubber Grommets 4" (100mm) Drill Hole, 3-2/4" (91mm) ID Single Side Plug Gasket for Cable & Wire Firewall Protection, Automotive & Electrical, Black

These are decent grommets, just a little thinner than I would like. For something made to go into a fairly large hole, these are a little thin and tend to end up inside whatever I am trying to install them on. Other than that, they are decent. The size is accurate and consistent and they are easy enough to work with.

I used this to penetrate through the outer shell of my mini ex to run my fan wires down into the battery compartment area. They come sealed, so you will need to slit an X into them when you are ready. I also need to run some wires through my firewall, which was the original intent for these, but I needed the tractor first.