One machine that walks and one that pushes. Turn the backrest round and the rollator becomes a transport chair with footrests, which is the honest answer for anyone who can walk a block but not three.
The footrests are included, and that is what makes the chair mode actually usable rather than a line on a box. The seat is 19.5 inches wide, wider than most rollator seats, because it has to work as a chair as well. It folds from the side rather than flat.
The number in the name is the seat height. The F18 sits at 18 inches with handles from 29.5 to 35, the F20 at 20 inches with handles from 30 to 36.5, the F23 at 23 inches with handles from 33.5 to 39. All three carry 300 lb.
Try it before you buy
 Key specifications: Weight to lift: 17 to 21 lb; Weight limit: 300 lb; Seat height: 18 to 23 in; Handle height: 29.5 to 39 in; Seat width: 19.5 in; Outside width: 27 in; Seat depth: 10 in; Between the handles: 19.5 in; Length: 28.5 in; Wheels: 8 in; Brakes: Hand brakes, tool free adjuster; Backrest: Full backrest, reversible; Bag or basket: Covered soft basket. Drive Medical figures.
 Frequently asked questions:
 Will the Airgo Fusion 2 in 1 Side-Folding Rollator go in my car? It folds. Tell us your car and we will check the fit with you before you decide.
 Does the Airgo Fusion 2 in 1 Side-Folding Rollator come in more than one size? Yes, in three sizes: F18, F20 and F23. The table above shows what differs between them. Everything else is the same walker.
 What height of person is the Airgo Fusion 2 in 1 Side-Folding Rollator for? Every height is covered: the F18 suits people up to 6'0" and the F23 5'10" and up.