XLAB Rocket Pocket XL Top Tube/ Stem Bag: BlackXLAB Rocket Pocket XL Top Tube Stem Bag: Black. The Rocket Pocket features an aerodynamic shape and a super smooth low skin friction exterior that reduces drag. Tapered aero design features a 72 degree front that fits tight up against the stem Non slip surfaces underneath and on the front of the bag redudes bag movement Silver colored interior makes it easy to find contents and features a stretch mesh pocket small items Proprietary insulation material