Introducing the Ortlieb Back Roller Pro Plus Pair. If you sometimes have trouble deciding which extra T-shirts to take along, or whether you should take one or two pairs of shoes, the Back Roller Pro Plus panniers have plenty of space for everything you need as it\\\'s the extra-large version of the popular Back-Roller Plus touring bag. With a volume of 70 litres per pair, it offers almost twice as much stowage space. It\\\'s also the first Ortlieb Back-Roller with an additional front pocket.