has a transparent bypass located on the stem to encase a filter for tars and other particles the transparent character will allow observers to view the filtration process application_number US 95752678 A description fig1 shows a pipe 10 having a bowl 11 and a stem 12 a heating pin 13 is positioned within the bowl 11 at its center the pin 13 projects upwardly from the base of the bowl 11 and is made of a heat conducting material preferably metal the heating pin 13 transfers heat from the combustion materials in the bowl 11 to a heating rod 14 one end of which is in contact with the lower end of the heating pin 13 within the bottom wall of the bowl 11 the lower end of the heating pin 13 is preferably threaded and screwed into a similarly threaded opening 14a on the end of heating rod 14 the pin 13 has a head 13a to assist in threading it into the rod 14 the heating rod 14 may have insulation positioned around it to prevent dissipation of heat and to keep the stem 12 from becoming too hot to the touch preferably the stem 12 itself is of an opaque insulating plastic construction the heating rod 14 should be a readily conducting metal such as stainless steel etc the heating rod 14 runs partly through the pipe stem 12 and terminates at an upturned portion 16 which extends into a water vapor filter system 17 fig3 a smoke passage 15 runs from the bottom.