Just used one of these on a 4-day trip in which I covered nearly 1000 miles. The bag held not only a couple of books and half a weeks' worth of socks, underwear and t-shirts, but also a big bag of almonds *and my laptop*. Really can't complain at all. Some of the reviews here complain about the size, about the length of the straps, etc., but for me it all worked great. People's bikes may have different seat sizes, but the straps were very snug (yet fully adjustable) on the back of my Ducati s2r. I'm not going to make assumptions, but it may be the case that some people can't figure out how to use the staps properly, because I could have made mine much tighter or looser, and was able to get the perfect fit. Also, once the straps are under the seat, the bag is "quick release" and can be removed and put back on simply by clipping in the 4 buckles. Bag is plenty sturdy too. Highly recommended for the price.z