The bike rack mountain bike and E-mountain bike users love the most - the Spider Rear Rack now has a pannier attachment to allow you to carry any brand of pannier so you can make your commute fun again. Simply attach the Pannier Receiver to your existing Spider Rear Rack for the weekday commute, keeping your panniers super secure with in-built top rails and a lower pannier catch anti-sway fingers (included with pannier receiver). Then swap back to your rear rack cradle for weekend adventures.