Snap Seal vials can accept aluminum crimp seals or Snap Top Caps. 2701H01 through H22 are aluminum seals, 13 mm with Septa; 2701H25 through H58 are Snap Top Caps, 13 mm with Septa. 2701H61 through H82 fit Shimadzu autosamplers. Compare this item 11 mm Crimp Top Aluminum Green Cap with PTFE/Red Rubber Septa PerkinElmer