Retro 1990s carbon fibre Mtb frame. Italian made by a company called C4 this is a crazy seat tube less design. Years ahead of its time with monocoque jointless carbon fibre construction, integrated seatpost clamp and internal cable routing. Size is a bit of an unknown, but I would guess at a large, the distance between the bottom bracket centre and top of (virtual) seat tube is 20.5. Condition is good, only minor marks from use, although the seatpost clamp is missing so a replacement would have to be fabricated. C4 were well known for eccentric designs and their road bike frames were equally impressive. Thanks for looking, please contact me with any questions.