Variables in Stopper/Vial Systems. Stoppers are West Products
↵a 4023 – bromobutyl-based, 4432 – chlorobutyl-based, 4031 – bromobutyl-based.
↵b 13 mm used for 2 R only, 20 mm used for 6 R only.
↵c 2 R – 4 ml overflow capacity, 6 R – 10 ml overflow capacity.