NOTE: Please choose the size according to the tire mark. The dimensions don't mean the length of the bike kickstand itself. Make sure there is enough space on the screw nut: 0.85cm. You don???t need extra strews or nuts since it uses the nuts that come with the bike. Convenient to park a bicycle. Ideal for a child who graduated from training wheels and learn to ride on two wheels. EASY TO INSTALL: Loosen the nut on the back axle of your bike, then install the kickstand into the bolt and tighten the lock nut. STURDY: This bicycle kickstand is made of top-quality carbon steel, more reliable than Aluminum Alloy. Strong and durable. NON-SLIP FOOT: Bike Side Kickstand with an anti-slip reinforced foot to prevent slipping, also helps maintain balance on uneven ground.