Aero road bike frame from A2 in Portland, Oregon. Frame is a 51, but measures 56 cm across the top tube, center to center. Agressive bike with internal cable routing, tire clearance for 32mm tires, and flat mount disc brakes (default 140mm). The seat clamp slides along the top of the seatpost so you can dial in a forward or rearward position. Great bike, I just needed to size up a frame size. There are a few really minor blemishes, see the photos. Currently has a sram dub bottom bracket installed. Headset is included. I was using a FSA ACR stem and the proper dust cap for the ACR is included as well.
For reference, I am 6ft with a 32 inch inseam. I think this frame would best fit someone under 5'10" or so.