Made from iron materials, this bike trailer coupler provides with increased toughness and durability. Easy to install, but not easy to fall off. Heavy duty, not easy to crack. With this bike trailer coupler attachment, the parent’s bike can be connected to the kids' trailers. When your kid is tired of riding, you can tie him next to your bike. Features -Color:Black -Material:Iron -Size(Traction head):9.00X3.00X4.50cm/3.54X1.18X1.77in -Size(Wrench):5.80X5.80X0.80cm/2.28X2.28X0.31in -Size(Hook):5.50X4.00X1.10cm/2.16X1.57X0.43in -Good workmanship, reasonable structure, professional and practical, easy to install and stability. -By removing or squeezing an easy-to-release nut or attaching the bike trailer coupler to the bike's rear wheel assembly. -The bike trailer hitch provides the critical connection from your trailer to your bike for quick rider changes. -Once you install them up, they will not easily fall off, which can ensure your babies safety. -It provides good stability and is compatible with a majority of bikes on the market. Package list: 1 x Trailer 1 x Wrench 1 x Hook