An ElliptiGo Stand up Bike! Stand Up Cycling! No Seat At All for a Rest? - YouTube
Can people ride a bike without a seat? - Quora
The Retrogrouch: Look Ma' - No Seat Tube!
BAOQI No Seat Fitness Bicycle, 20" Dynamic Cycling Bike, Folding Exercise Bike, Portable Bicycle, Dynamic Stand Riding Exercise Bike (blue), Exercise Bikes - Amazon Canada