Columbus tubing

Brain - We strongly recommend Columbus Brain for cyclecross designs. This tube set is an excellent choice for creating a light, tough and strong cyclecross frame. Brain tubes feature round over-sized diameters that offer good resistance to accidental impacts. This allows for excellent durability for the life of the frame. Brain Tubes can either be lugged or fillet brazed. Large choice of wall thickness and butted diameters to strengthen your cyclecross frame. Brain tubing can also be used on either a road or track frame.

Literally Googled Columbus Brain Tubing, this was the second link...