Stems are one of those component items that should be strong, light, and failure-proof. In some circles, working with both carbon-fiber and aluminum at the same time is the key to the future, and many will tell you that the lightest, strongest, stiffest parts will have an aluminum skeleton and carbon wrap. This is the genius behind the PRO Vibe OS Carbon Road Stem.This stem is formed first from thin-walled 7050-T6 aluminum, then wrapped with uni-directional carbon fiber to seriously stiffen the structure. The carbon adds twist-resistance with almost no weight penalty. But it's more than just a boom tube with clamps on the ends. The stem itself has been engineered for greater stiffness. It isn't a round tube, but a triangle, with a thicker wall across the top of the triangle and then thinner walls on the V. It's also been redesigned with what PRO terms a Puzzle Clamp. So rather than using a traditional 4-bolt faceplate that could be prone to flexing, PRO's new design wraps up and over the top portion of the stem. The "V" shaped protrusion acts like a bollard that accepts the corresponding strap on the faceplate. Under tension, the two parts fit together perfectly, only tightening the joint further and becoming absolutely motionless.Because this design is directional, the stem is not intended to be flipped over, but always positioned at a -10? angle. For added emphasis of the design, the handlebar clamp plate has a V as the central design element. This V highlights both the name of the stem and the shape. The plate is made from 7050-T6 aluminum as well.To keep the PRO Vibe OS Carbon Road Stem as light as possible without sacrificing strength, titanium bolts are used for both the handlebar and steerer tube clamps. The handlebar clamp is designed for 31.8mm handlebars; the steerer tube clamp is designed for 1-1/8" steerer tubes. The stem comes in 80-130mm lengths, with stems available at 10mm increments. It has a matte clear carbon fiber finish.