11mm Snap Top Caps™. J.G. Finneran. Use with Snap Ring™ or Snap Seal™ vials Snap on and off easily No sharp aluminum edges 2686S94 through 2686T10 are Polypropylene GC Snap Top Caps. 2686T21 through T42 Snap Top Caps are for Shimadzu Autosamplers. All caps are 11 mm. Caps may be snapped on and off.