TEMO 100 PC 1/2 inch (13mm) Sand Drum Grit 60 Coarse with 2 pc 1/8 inch (3mm) Mandrel fit Dremel and Compatible Rotary Tools 100 PC 1/2" (12.7mm) sand drum with 2 Mandrel fit dremel grit 60 coarse 100 piece 1/2" (12.7mm) 60 Grit, 1/2" (12.7mm) Diameter 2 piece 1/2" (12.7mm) X 1/2" (12.7mm) Rubber Mandrels 1/8" (3.175mm) shank size (Fit Dremel and other Rotary Tools) Mandrel head size can be adjusted with the screw at the top. You can adjust it smaller to slide in sand drum or adjust it bigger to hold sand drum tight.