I’m down to two backpack choices, both Samsonite. https://www.amazon.ca/Samsonite-77234-1073-Wheeled-Backpack-International/dp/B06XXJY641/ 21.0" x 14.0" x 9.0" and https://www.amazon.ca/Samsonite-Wheeled-Backpack-Black-Charcoal/dp/B00102M140/ 19 x 10 x 13 the latter is heavier but has good reviews vs no reviews on the first. I don’t know which one is more durable. I’ll likely be carrying it on my bike to the train in a Givi E460 top case with the dimensions of 22.3"L x 11"W x 16.6"H (46 Litres). If durability is the same I'd go with the lighter one. I'm not too worried about waterproofness because the top case will be mostly waterproof.