Premium quality aluminium ball castors Ideal for all types of chairs and sofa's, beds, foot stools, and most pieces of furniture They are very suited for heavy pieces of furniture, making them easy to move on carpets & rugs These high quality castors are used by the better quality furniture makers. The castor's wheels are 50mm / 2" diameter The castor's comes complete with its own new sleeve for fitting Simply remove the whole of the existing castor and sleeve. Tap the replacement sleeve in with a hammer. insert the new castor into the sleeve. If you need to drill a new hole, use a 10mm or 3/8'' drill