Mr. Heater 4 Inch Vertical Vent Kit for Big Maxx MHU75LP and MHU75NG  Unit Heaters #F102848
The F102848 vent kit is to be used for vertical venting only for the MHU75LP/MHU75NG only. It includes one 4" gas vent cap, one storm collar, one adjustable roof flashing, one adjustable ceiling/wall thimble, one 4" elbow, one piece of 4" x 36" double wall pipe and two pieces of 4" x 24" single wall pipe.