Sold as sets of 4 these chair glides fit the Herman Miller manufactured Eames Wire Base chairs with fiberglass seats manufactured from the mid-1970s up to 1993 in the USA. 

These do not fit current models manufactured by Vitra for Herman Miller or knock off chairs. There can be some small size variance with the ball these fit on as different factories were involved in the manufacturing process. Generally within the date range they work well.

Dimensions: 27.5mm base / 10mm opening.