Rover Bike Trailer Coupler vs Oulii Bike Trailer Coupler Hitch Adapter

The Rover is the safer pick for most shoppers. It is a purpose-built steel coupler for Retrospec Rover kids', cargo and pet trailers, it attaches at the rear axle nut, and owners rate it highly for fit and function. The Oulii is a generic carbon steel adapter with a retractable arm and an integrated hitch pin, aimed at e-bikes and cargo wagons, but its listing is muddled and it carries no written warranty. Buy the Rover if you tow a Retrospec trailer; consider the Oulii only if you need a longer, retractable arm for an e-bike or wagon and can confirm the fit yourself.

• Choose the Rover if you own a Retrospec Rover kids', cargo or pet trailer and want a factory-fit steel coupler for a second bike.
• Choose the Oulii if you tow a cargo trailer or wagon behind an e-bike and need a longer retractable arm with a built-in hitch pin.