These 'tailored plus fours', as Rapha call them, use the remarkable Schoeller Nanosphere fabric, which is surprisingly water and stain-resistant.
They also have a slight stretch to them, which suits their improved slimmer cut over last year. There are belt loops, though I found sizing spot on. The tweed lining inside the two deep front pockets and zippered rears is typically Rapha. More practical touches include buttoned adjustment at the legs and slight padding at the seat - so they perform as good on the saddle as they look off it.