The website is very clean and it is easy to find what you want. I have always found the size designations (S, M, L...) to vary widely from manufacturer to manufacturer. The sizing chart for the item on the LeatherUp website cut through all the uncertanty and the fit is exactly as I needed. The denim shirt feels solid I expect it would be warm on those early spring days. I would not consider this is not a winter top layer for temps under 40 when riding but it would probably still keep you warmer than a light jacket when not riding. Seams are tight and overall construction is high quality. Can't wait to get on my bike this spring.