CHM® 8-425 Autosampler vials & closures. CHM 2 ml 8-425 neck autosampler vials, caps and septa are compatible with all common autosamplers including Aijiren, Waters, Shimadzu, etc. These smaller opening vial with an 8-425 thread size screw cap are uniformly flat bottom for security with the inserts. PTFE/Silicone septa are most popular for HPLC