This is a great repair/replacement for the plastic gliders on our old iron patio chairs. Perfect fit. And the package contained twice what we needed, which is ok with me, as I suspect their longevity is limited to a few years. Easy to install.Tips. Measure your chair. When measuring, make sure the old glider is completely removed. The inside diameter must match the replacement. On our chairs, the old gliders were missing, and I found a few had part of the old glider remaining inside, which I pried out with a flathead screwdriver.Use a rubber head hammer to tap the glider into place. Do not use any glue or adhesive when installing. Do not use any oil or lubricant when installing. If you paint the chair before installing, let the paint dry thoroughly, then apply some heat with a hair dryer or heat gun insure the paint is dry. Heat sparingly to avoid destroying the paint.I gave durability a 4-star rating because I am clueless as to how durable they really are. The durability of similar gliders on my other chairs has been very good. This is surprising as we have a concrete block patio.