Bike trailer coupler for instep and schwinn Why you need a spare bicycle trailer coupler? This 12.2mm bike trailer hitch coupler for Instep and Schwinn allows you to attach an Instep or Schwinn bicycle trailer to almost any bike. With an additional coupler attachment, 2 bikers can tow the trailer in turn and don't need to spend much time disconnect and connect the trailer to different bikes. Some bike may need QR adapters If your bike's drop out is not flat enough, you may need a QR adapter to get it attached.(If your installed some axle-mounted accessories such as kick stand or a rear rack, you may also need a QR adapter to get enough space for this coupler.) Premium bikes may need Thru Axle adapters Preminum bikes use a carbon fiber frame, using a thru axle adapter for installing will greatly cut down the risk of damage your expensive bike. What's include: 1 *Lock Pin, 1 *Coupler, 1 *Lock washer.