Freewheel cog (screw on type). Easy to install by screwing on by hand and pedaling will tighten this.
Shimano RD-TZ500 6 Speed Direct-Mount 6 Speed Rear Bike Derailleur
20 Inch Kids Boys Bicycle 6 Speed Mountain Bike Children Bicycle MTB Bike 20 Inch
Women’s 6 Speed City Bike 700C Hybrid Purple
Shimano MF-TZ500 6 Speed Bicycle Bike Freewheel 14- 28T Index - Screw On
6 Speed Racing Bike / Bicycle Non Index 14 - 24T Screw On Freewheel
