Magnetic headspace crimp cap to suit 20mm closure autosampler vials. 20mm diameter cap, with Silicon (white) / PTFE (white) septum (3mm thick). 8mm diameter hole. 100 pack. Please see below for compatible vials. 20mm Magnetic Crimp Cap (8mm hole) with Septa, White PTFE, White Silicon (3mm thick) | 100 pack. £ 34.30.