CHILDHOOD Adjustable Variable Speed Bike Training Wheels for Girls Boys 18 to 22 Inch PACKAGE INCLUDE: 2 x training wheels, 2 x wheel bolt, 2 x screws, 2 x sleeves,1 x extend bolt. Please Note that there's only ONE extend bolt, installing on the side of Variable Speed wheel. WEIGHT BEARING CAPACITY: These training wheels can bear the weight of 100 lbs,but the load of 70 lbs or less will be more suitable for the wheels.They can bear children's weight without security problems. APPLICAPLE BIKE SIZES: They are suitable for bicycles sizes of 18 inches, 20 inches and 22 inches. Pleases make sure that the training wheels are 1/4 to 1/8 in higher than the ground. STRONG AND DURABLE MATERIAL: These bike training wheels are made of high-quality steel and anti-shedding rubber tire.They are very sturdy and durable, which can keep bicycle beginner stable and help child learn to ride a bike without slipping. WARM TIPS: Please note that our training wheels enclose with installation instruction in package. Make sure if your bike is fit or not before ordering. Please feel free to contact with us if you have any questions.