The altura arran expanding post pack is ideal for every day use or commuting as you can expand the bag to suit the amount of gear you39re using the main compartment expands and it has a zip closure so you can safely store any valuables there are also side zip storage pockets as well as bungee storage straps to keep any extra layers easy to access this handlebar bag post pack has a quick release fitting system which allows you to easily mount and dismount it whenever you like the post pack