The discontinued PaceSaver Passport series was a trio of very similar scooter models that differed only on their wheelbase and tire sizes. Most parts were fully interchangeable between the three Passport models.
Passport Junior 3-wheel:
9" pneumatic front & rear
Passport Premier 3-wheel:
9" or 10" pneumatic front & rear
Passport IV 4-wheel:
10" pneumatic front & rear
All PaceSaver Passport scooters require two 12 volt U1 batteries.