Not normally one to write reviews but have been blown away by how good this bag given what I consider to be a very reasonable price. The bleed valve is brilliant for allowing you to fold the bag up nice and snug. The bag needs to be packed appropriately to give it structure against the seat post but once done stays in place with a good tug on the securing straps. If I was to have the tiniest of criticism it would be the buckles are a tiny bit fiddly and can be put in crocked. But to reiterate my overall opinion this is a brilliant bag that's been well thought out and does the job more than adequately.

Bought this for a two-day tour around the west-country on my road bike. After spending a bit of time working out how best to pack it and attach as securely as possible it worked really well at carrying approx 3 litres of light clothing etc. This is probably the minimum you could carry in order to get it tight and secure on the bike. I haven't carried more then that. The bag worked really well and I am happy with the purchase, especially at the sale price. Thanks Sigma & Vel!