Seatpost Rack

Information from: http://bontrager.com/model/06971.

The perfect choice for frames without built-in eyelets, this versatile rear rack quickly attaches to your seatpost with an easy to use four-bolt design. Compatibility with Trek's Interchange System means it mates seamlessly with a variety of Interchange bags designed to install fast and securely.

Features

Fits both 27.2mm and 31.6mm seatposts

Compatible with Trek and Bontrager Interchange trunk hardware for quick and easy bag installation or removal

Designed to carry up to 25lbs (11.3kg)