Just seen this on the arrowhead blog: http://www.alpkit.com/spotlight/arrowhead/
an airlock dry bag as a rack bag - totally waterproof and really cheap
http://www.alpkit.com/shop/cart.php?target=product&product_id=16469&category_id=250
about to get one
an airlock dry bag as a rack bag - totally waterproof and really cheap
http://www.alpkit.com/shop/cart.php?target=product&product_id=16469&category_id=250
about to get one