ND9mm Screw Thread Autosampler Clear Lab Vials are made of clear Type 1, Class A Borosilicate Glass with a writable label for sample identification. 2. 2ml HPLC Vials with Unique Thread Design Ensures Consistent Seal and Can Be Reused, Not Volatile, Easy to Use 3. 2ml Capacity,12x32 mm Dimensions, Screw Thread 9-425 Neck,100/pack 4.