O-ring Less Screwcap Tubes Line UP for Test Sample Containment

Double-sealed design, Leak-less even without O-ring 1st sealing point where the protruding part is located inside of the cap makes the clearance between the cap and the body seal. By fully tightening the cap, 2nd sealing point makes both upper and main body seal completely seal, resulting in preventing test sample leakage and evaporation.