Standard neck vials 8-425 thread finish fit most autosamplers that accommodate the 12 x 32mm vial format. Made of superior quality 33 expansion Borosilicate Clear Glass (Type 1, Class A) or 51A Amber Glass. Uniformly flat bottom for security with inserts. I-D™ vials feature write-on patch with graduations at 0.5, 1.0, and 1.5 mL.