To keep your trap on your belt, you’ll need a holster. These are made from aluminium plate, covered with leather with a V hook to hang your trap from. A number of sellers on the gbfans for sale section sell these, most coming with the v hook attached. There are two variants. The standard and the Venkman. The standard has a pop stud strap that wraps around your trap when holstered helping keep in place, the Venkman holster does not.
Throughout the film, we’re never shown where the PKE meter is stowed on Egon’s uniform. It appears and disappears when not in use. It’s far too big to fit comfortably in one of the pockets.
Some fans have remedied this by creating PKE holsters. Tyger Cheex on gbfans and the UK Ghostbusters forum offers a fantastic holster very in keeping with the gizmo pouch and the radio holster.