Flow Control Hose Clamp For Tube Size: 6mm-12mm / 1/4" - 1/2". Tubing Clamps for Master LC Mushroom Lids (Tube Lids). Used to prevent backflow. For tubing 1/4''-1/2'' OD. Adjustable Hose Flow Control Shut Off Laboratory Pinch Valve. Six (6) adjustable positions to control liquid flow. Autoclavable.