The Expert for Wood ball bearing set contains guide ball bearings of various sizes for different milling purposes. 1x 9.5 mm (a) / 4.76 mm (b) + washer 2x 12.7 mm (a) / 4.76 mm (b) + washer 1x 16 mm (a) / 8 mm (b) 1x 22 mm (a) / 8 mm (b)