METAL STEM & Screw thro bowl
Made by Filto Pipes Inc, of Burgaw, North Carolina, inventor Robert L.Smith, US patent # 3170468 23rd Feb 1965. The stem, sealing ring and filter holder design mentioned in design by Aristocob.
The bowl and stem are in a great variety of colours, all interchangeable.
The spring clip in the bit assists in holding the filter in place.
There are two versions of the stem, one with a spun front end, and more common, with a plastic push fit end cap