Headspace Crimp Vials, 20 mm – Restek Flat Bottom. Product Name. Headspace Vial. Products Often Purchased with 27 mL, 20 mm Headspace Crimp-Top Vials, Clear, 100-pk. Vial Storage Rack for 6, 10, or 20mL Headspace Vials, 36 Vial Capacity, Polypropylene, ea. 20mm Magnetic Crimp Cap w/PTFE/Sil