Product Description: 1. This item is a practical bike trailer hitch for towing solutions. 2. With the complete hitch arm and hitch connector, easy to install without other tools required. 3. Unlike conventional bicycle towbars, our towbars have additional corrugations at the front and rear. 4. These ensure a better and more secure grip on the quick release 5. It is perfect for children and dog trailers! Installation method: 1. Install the connecting rod and lock the fixing buckle 2. Install the bicycle holder on the left rear hub of the bicycle 3. Install the connecting rod and the fixing frame, buckle the fixing buckle and lock the traction rope (double protection) Product Specifications: Product material: carbon steel Product weight: 140g Product color: black Product size: 54*48*15mm/2.12*1.88*0.59in Shaft hole diameter: 11mm/0.43in Diameter of recessed area where axles nut is tightened: 18mm/0.70in Entrance hole diameter at trailer connection: 7mm/0.27in Product List: Bike trailer hitch coupler*1 Note: 1. Due to the light and screen difference, the item's color may be slightly different from the pictures. 2. Please allow 0.5-2 cm differences due to manual measurement. See more product details 1.High-grade Material: Our Coupler Adapter Attachments are anti-rust and anti-corrosion, made of black enamel coated steel, precision welding technology makes it strong and durable, not easy to break, and suitable for long-term use 2.Safe Connecting Design: Put it on the rear axles, you can hang the trailer at any time, the Bicycle Trailer Hook Attachment is equipped with a connecting pin, it is difficult to open after installation, and the hook is not easy to fall off, ensuring the safety of babies and pets. 3.Lightweight & Portable: The Hitch Connector Coupler will be a handy accessory for its small size, which is easy to carry. Parents bikes can tow the kid's trailer, your kid will love to ride the bike. 4.Easy to Install: Our Coupler Hitch Attachments are easy to install, just remove or tighten a nut, and you can easily release or attach it to the bike's rear wheel, which can be applied to instep bicycles, pet carts, etc. 5.Widely Used: Our Connector Accessories are widely used in trailers for children, pets, etc., suitable for most bicycle rears, please confirm the product size before buying to make sure it fits your bike.