2" discs. The plastic holder is pretty basic and I had to use a flathead screwdriver to pry off a couple of adapters because the plastic part of the holder was a bit too big, but after I cut some of the plastic with a sharp knife the adapters popped up and came loose. much easier. This is a staple in any tool kit and is great value for money. The ball bearings fit well with enough spring tension to properly hold each clutch.