Standard Opening Screw Thread Vial, 12x32mm, 8-425 Thread, 2ml. Standard narrow neck design ; Optimal performance w/ Shimadzu, Varian, Hitachi (Our Standard vial is versitile, & will also perform well with most instruments including Aijiren & Waters) 33 expansion boroslicate glass (Type 1, Class A) I-D Vials provide graduated write-on marking