Stan's No Tubes Downhill Rim Strip
Stan's Downhill Rim Strip converts standard tubed wheels to tubeless so you can reap the benefits. Going tubeless allows you to run low tire pressure for better traction while drastically reducing the chances of a flat. Stan's rim strips create a tight seal with the tire bead, reducing the instances of "burping". Plus, you won't miss dealing with flat tires and you'll save money on tubes!
The Downhill Rim Strip fits most rims that are 36 - 39mm in width.
Mountain Bike Tire Installation on Stan's Tubeless Wheels - Stan's NOTUBES