Uxcell a15032300ux0424 Luggage Sliding Slides Ball Transfer Units Conveyor Roller 10 Pcs, 1.2" width, 0.63 Metal Product name: ball transfer unit; material: metals Fixing hole diameter: 4 mm/ 0.16"; hole distance: 38Mm/1.5" Ball diameter: 16 mm/ 0.63"; total size (approx.): 48X 32 x 20 mm/ 1.9" x 1.2" x 0.8" (l*w*h)