Love my Topeak click-on bar bag. It has an over the shoulder strap that converts to a waist strap so it can be used as a fanny pack, too. We also have a Cannondale (road) tandem. Topeak makes 3 sizes, I use the small one on both tandem and half bike. The quality is second to none and the price is right. Wiffie uses middle size. You know women, never enough "purse" room.