Shaoxing ALWSCI Technologies Co.,Ltd is one of the leading China 18mm open top screw cap manufacturers and suppliers,Website:://.alwsci.com, welcome to wholesale cheap 18mm open top screw cap, headspace vial rack from us.                      FEATURES1.Caps are made of magnetic precision metal to exact manufacturing tolerances and lined in a controlled manufacturing environment.2.Pre-slit septa are easier to pierce with needles.3.Pre-assembled caps and septa are convenient and minimize contamination from handling.