XLAB Duo Cage Pod: BlackXLAB Duo Cage Pod: Black. The Duo Cage Pod includes two compartments for organized storage of large and small items. Fits any standard size water bottle cage. The large chamber (600mL) is designed for items like tubes or CO2 cartridges The small chamber (83mL) is designed for items like cash and house keys Both chambers are water proof Includes a micro fleece bag that prevents rattling