20mm Crimp headspcae Vial Widely used in GC/MS particles from machinery wear Accurately capture improve efficiency Caps are made of high quality aluminum,precise manufacturing tolerances. Precision data in lab Crimp Headspace Vial parameter 1. 20 mm Aluminum Crimp Caps for Headspace Crimp Vials ND20 2. 20mm Crimp-top Aluminum Caps with Septa