6-20mL 20mm Crimp-Top Headspace ND20 - Hplc Vials product description. 1.Bevelled top design. 2.Available with amber or clear vial. 3.Available with 20ml or 10ml vial. 4.Magnetic Aluminum cap suit for CTC instrument. 5.Butyl/PTFE, Pharma-Fix-Liner (Butyl/PTFE), Silicone/PTFE are all Available. 6.Rounded or flat bottom profiles are available for accurate instrument compatibility.