several sizes, but most importantly - waterproof, and have necessary securing straps.
http://www.ebay.co.uk/itm/like/Passenger-Seat-Bag-SW-Motech-Drybag-600-BMW-R-1100-R-yellow/391292578886?hlpht=true&ops=true&viphx=1&_trksid=p5197.c100068.m2280&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D20140211130857%26meid%3Df3a8a7c563d84d9983c0b0f76d823301%26pid%3D100068%26rk%3D2%26rkt%3D6%26sd%3D401010000048%26clkid%3D651391609710723793&_qi=RTM2063741
Al
