I have for sale this Givi tank bag, which is compatible with their tankring system, but you will need to add the tank ring to fit your bike. The bag has a 20 litre capacity and is in very good used condition. It has the following features: • Water-resistant zips and reflective inserts • Rain cover in fluorescent material • Weatherproof internal compartment to store the raincover • Additional inner-liner against dampness • Removable tablet-holder and cable port • External pockets are removable to form a separate bum-bag This is no longer made, and has been replaced by a 15 litre version with fewer features. Cheapest I can find it is £79. You can have this one for £50 delivered in the UK.
