Aluminum Cap for HPLC Autosampler. The aluminum caps produced by Aijiren are all high-quality, and it is easy to wrap the Vial caliber to form a sealed space under the hand crimper. The 5.5mm center hole also ensures easy sampling of the autosampler. Rated 4.9 /5 based on 467 customer reviews. 11mm cap aluminum cap crimp cap crimp top cap hplc cap.