Vials are of high quality Original Aijiren Technology ™ 4ml WISP ™ autosampler vial type. 4ml vials are compatible with 13-425 screw thread closures. HPLC / GC Compatible – Aijiren Technology TM, Aijiren technologies, Shimadzu, Perkin Elmer, Thermo, Jasco etc. Vials Quality – USP type 1 class A, 33 Expansion or 51 Expansion. Cap – PP cap closed or open.