51cm CAAD8, Alloy frame with carbon / alloy forks. Actual measurements are top tube c-c 520mm, seat tube c-c 475mm, c-t 510mm, head tube length 140mm. I would say it will accommodate riders between 5'6" to 5'9". Frameset is in excellent condition with only some very small marks, 1 paint chip on the downtube and a few small chips on the RH seat stay. Has mudguard eyelets so a good winter bike.