I purchased this bag as my 70l version was too big for what I wanted. It’s a great bag. It’s sturdy and seems well made. It fitted very well to my pillion seat and with just the provided straps felt very secure. It didn’t effect my riding seat or position and didn’t effect the balance of the bike. I needed to carry some awkward heavy items including boots. The boots just fit into the two sides that over hang the seat. I’m very pleased with this bag and will use it again definitely. Obviously it’s time consuming to fit but that’s not really an issue. I haven’t tested the it’s waterproof capability as it didn’t rain. I feel though it would keep the rain off. Great for a weekend away.