VWR® Crimp Caps for 20 mm Clear Crimp Seal Headspace Vials. Supplier: VWR International. Description: VWR Crimp Cap, 20mm with 9.5Mm Hole, Thickness: 3 mm, Cap color: Silver, Cap material: Aluminium, Septa type: Gray PTFE/Gray Butyl Rubber, Pharmafix, to fit most headspace autosamplers. New Product.