The altura vortex seatpack has been engineered to fit around your seatpost whislt providing adjustability for different seating configurations the vortex is super light weight and also fully water proof which makes it ideal for the all weather cyclists or keen commuter designed to cater for individual needs by providing lash points a rear light loop attatchment and a roll top closure whcih allows you to keep the content of your bag tight together allowing no room for movement overall this vo