The specification is 12*32mm. Standard GC, HPLC vials, small diameter, 8-425 standard threaded ports for autosampler and sample storage. Can be used with 8-425 threaded cap closures. The 8-425 2ml screw vials is equipped with a screw cap of 8-425 thread size, with black and white open caps, solid caps and various septa for different applications.