These tighten the space created by a bearing rubbing the housing of the gauge wheel. You can put this in either half of the gauge wheel housing. This will give you more life instead of having to buy another half of a rim or a total assembly. Sometimes these help the wheel last a long time more and sometimes only another couple seasons. For all John Deere gauge wheels that go onto air seeders and drills in the 95, 90, 60, 50 series, and even planter wheels that use the same bearings.