The top of the range regarding the Bikepacking bags Underworld. The Blackburn Olite Seat Pack Outpost School has an expandable capacity from 5.25 to 6.95 liters, vent valve to minimize the size, waterproof seams, suitable for standard and telescopic bras. It has an aluminum bearing structure that remains firm to the bike even when it is subjected to strong vibrations when crossing disconnected sections of soil and a detachable bag. The bag has a vent valve to reduce size. The valve is one -way and therefore does not make the air or anything else. Dimensions: empty length 356 mm and 483 mm in its maximum extension, height 165 mm and large large 190.5 mm.