Crimp Top 20mm Silver Aluminum Vial Cap with Gray PTFE . Aluminum crimp-top cap, 10mm center hole, 20mm diameter, with gray PTFE/moulded butyl septa, 100/pk, CV2021. Stock Ships in One Business Day, Free Samples 20mm Flip Off Caps-100 Pcs Aluminum-Plastic Red – Premium Vials. Color: RedFeatures: Quantity: 100Material: Aluminum-plasticSize: 20mm.