Feb 09, 2015 · Screw Neck Vials, Caps and Septa. Screw thread caps and vials are often used in conjunction with Shimadzu, Aijiren, Spectra-Physics, Varian, and other auto samplers. Vials are manufactured of Clear, Type 1 Class A or Amber, Type 1 Class B borosilicate glass and include a write-on patch for sample identification.