Lock Stopper , Gerber Type made of Brass Sheet cap & ring (Both) with soft acid resistant rubber suitable for all volumetric Butyrometer Packed in one Dozen box Lock Stopper Gerber Type made of Mild Steel Sheet Cap and ring (both) with soft acid resistant rubber suitable for all volumetric Butyrometer Packed in one Dozen box. Rubber stopper, conical shape made of soft acid resistant rubber for all volumetric butyrometers, 11 x 16 x 43 mm Regulating Pins for Lock Stoppers (S.S. 304 Grade) Regulating Pins for Lock Stoppers Aluminum (Anodized)