Compared to conventional stainless steel materials, our carbon steel bicycle coupling is more stable and firm, resistant to deformation and rust, and offers a longer service life. To use, first attach the towing hitch to your bike, then connect the bicycle trailer using the included pin. Installation is quick and easy, typically completed within minutes. The coupling secures firmly, minimizing the risk of accidental disengagement or loosening during use, helping ensure a high level of safety. Constructed from carbon steel, this coupling is durable and built for reliable performance. Product dimensions: Length: 5.7 cm, Height: 3 cm. Compatible with most bicycles, including mountain bikes, folding bikes, standard bicycles, and various trailers such as child trailers and pet trailers. Item Name: Trailer Coupling Material: Carbon Steel Features: Rust-resistant, Heavy Duty, Wear-resistant, High Hardness Size Details: Trailer Coupling: Length: 5.7 cm / 2.24 in, Height: 3 cm / 1.18 in (Approx.) Notes: Due to lighting and screen setting differences, the item's color may vary slightly from the images. Slight dimensional variations may occur due to manual measurement. Package Includes: A: 1 x 90-Degree Trailer Coupling, 1 x Buckle B: 1 x 135-Degree Trailer Coupling, 1 x Buckle C: 1 x 135-Degree Trailer Coupling, 1 x Quick Removal Buckle D: 1 x Trailer Coupling, 2 x Buckles