The Synchro-Stem patent for Kaywoodie's Drinkless pipes was applied for in 1929 and granted in 1932.
The system consists of a screw-in attachment combined with the earlier Drinkless patent.
The stinger's lenght is variable in order to fit the length of the shank.
This flexibility was facilitated by the manufacture of the aluminium attachment at Kaywoodie's plant.
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The Drinkless patent references were etched on the stinger.
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