This slides over most all walkers to protect the legs. Where most use expensive tennis balls, this takes about $0.25 of filament and lasts months. I have used PLA+ and PETG and both work fine. I print at 0.28 height solid. There is a ware groove to know when it is time to reploace. The groove is the last solid layer to the bottom. At .28 that is 36 layers.