Looking for a spacious, rigid, and weather-resistant pannier for your bike trips? The Topeak MTX TrunkBag is here to meet your needs. Thanks to a unique material process, this pannier is not only the largest in the MTX series but also rigid and weather-resistant to protect your belongings in all weather conditions. Its expandable top section and rear bottle holder make it a practical and functional pannier. But that's not all! The side panels can be extended to form full panniers, increasing its storage capacity. The Topeak MTX TrunkBag is compatible with all MTX QuickTrack® racks with removable side frames. However, note that double MTX side frames are required to use panniers on MTX BeamRacks.