Ritchey's WCS Carbon 4 Axis Stem combines the best properties of aluminum and carbon by joining the two! The 4 Axis stem features a carbon exterior with a 3D-forged 2014-aluminum core for super lightness and more strength than pure aluminum. Plus, this sweet stem offer fatigue resistance considerably better than offered by carbon only. You also get Ritchey's safe-and-secure Bias Clamp, and a 4-bolt faceplate with titanium bolts for even more weight savings.
Stem length is measured along the side of the stem from the center of the steerer to the center of the handlebar clamp (see diagram). Keep in mind that as a stem provides more rise, its effective length decreases. In the example above, if the +17-degree stem measures 135 mm, it actually extends 108 mm parallel to the ground.