【SIZE REFERENCE】 -20" wheel tricycle suitable for rider height: 4'8"-5'4", 24" wheel tricycle suitable for rider height: 4'11"-5'9", 26" wheel tricycle suitable for rider height: 5' 3"-6'2". 【FLEXIBLE 7-SPEED TRICYCLE】 - 3 wheel bikes for adults with seven-speed is for easy and quick speed change.