They are available in several widths in both long and short versions, i only use the long versions . Ii use the 40mm width items as the widest tyres i use are 35c and the narrowest are 28c and the chainstays on my bike wont accept any wider anyway.
Lately i have been looking at a new frame and fork from soma fabrication , their randonneur and the new Reno Rambler , either way i will need some 60mm guards , there are also those from Velo Orange , they are very pretty and the mounting hardware is more rugged but they cost a lot and are never in stock in the correct width when i have went to buy them !
The Stratton on the Union Canal in Edinburgh .