Prime-Line Products N 7449 Door Roller Assembly, 7/8 in., Convex, Plastic Tires, Steel Bracket & Ball Bearings, Pack of 2 Used as a top roller assembly on pocket door and by-pass closet door systems 7/8 in. outside diameter wheels Convex edge wheels (round edge) and Comes in a pack of 2. Constructed 4 of plastic wheels with steel ball bearings, assembled to a steel bracket Note: If product sold by Amazon.com and looks like image on this page, then rollers DO have ball bearings. Nylon ball bearing rollers Steel constructed bracket Can be used on bypass and pocket doors Comes in a pack of 2