Mini single position on/off clamp (C4767-1) gives positive shut-off with fingertip control. Use for thin-walled tubing under 4.7mm (3/16") O.D. The Mid-Range Clamp (C4767-2) has 15-position stepped adjustment that controls flow from full open to complete closure. Fits tubing from 3.2mm to 11mm (1/8" to 7/16") O.D. The Maxi Clamp (C4767-3) is for tubing up to 19mm (3/4") O.D. This clamp has a 12-position ratchet control from full open to complete closure.