Medium size. Selling for give away price because the internal cable guide for the front mech is broken so havent been able to feed the front mech gear cable through. Besides that frame is in great condition no scratches. had to buy another frame due to Ironman in a few weeks so this now in a box. It can be used with a single chain ring in front or as a track bike but Sigma say they have fixed this before but unfortunately I cant be without a bike for a week. Great deal.