METAL STEM & Screw thro bowl
The top pipe here, compared to the other version. This one is presumed to be an earlier "Sweetheart", with the stamping on the top face of the shank in script and below that word is "MADE IN U.S.A. PAT PEND".
The shank is a fluted hexagonal cross section and the internal filtering device permits ingress of air from the front of the pipe on drawing on the pipe.
Overall length 5 5/8 inch (143 m/m)
A patent was filed in 1958 and was issued on Aug 7 1962 to a Philip J Stieger of St.Paul Minnesota... US Patent #3,048,179. This varies quite a bit from the actual production pipe