Ibera Bicycle Reflective Trim Wide Opening Strap-On Saddle SeatPak Bag, 1 L/Medium Ibera's IB-SB9-M is the medium size of IB-SB9 (also IB-SB9-L) An internal mesh sleeve provides a divider for wallets, keys, or a small camera An additional Velcro strap secures the bag to the seat post of the bike It has double zippers that allow most cycling essentials to be stored with easy access Reflective trim and a taillight hanger help add to rider-safety