Really pleased with my spiral rolltop bag. I got the big 30l one and it is caverness. More than ample for a couple of 15 inch laptops, an 11 inch tablet, chargers, pencil case, glasses cases, water bottle in the outside pocket, over ear headphones in a case, shoe shining kit, external battery pack, and other odds and ends and it's not even half full. I'm pretty sure there enough room with some careful packing for a change of clothes and a toiletry bag for an over night stay. It's well constructed, most definitely water proof once zipped up and rolled. It did need a quick airing out when it arrived to get rid of the funky manufacturing smell inside but apart from that really, highly recommended.