After perfection was achieved with the standard alloy WCS 4-Axis stem, Ritchey's designers went back to the drawing board and produced a stem that is stiffer and stronger with minimal (a few grams) weight penalty.
Ritchey states the stem is a 4-Axis design enhanced with Matrix carbonalloy technology. This means the stem has a 3D net forged 2014 alloy core that is encased in high-modulus carbon fiber. Imagine taking a standard 4-Axis stem that has been pared down to a super thin thickness then wrapping it in carbon fiber. You basically have a thin 4-Axis core with a thicker carbon contain/layer enveloping it. Very clever design that works. It improves fatigue strength over the alloy version of this stem(not that that was ever a problem), but more importantly and relevant is the fact it makes the stem stiffer and provides better dampening from road vibration. Those two qualities alone are worth the price of admission. On a cosmetic note, the stem is absolutely beautiful. The UD carbon fiber with gloss coating is a real eye catcher and is right at home on any high-end steed. It also matches carbon fiber woven bars perfectly and also matches well with UD bars.
The Carbon Matrix stem has all of the other features of a 4-Axis stem. The fork steerer clamp has a slot that is cut on a bias(angle) with opposing bolts to allow the stem to be secured with less torque. This makes clamping the stem to a lightweight carbon or butted alloy steerer tube safe and hassle-free. The face plate has a forged core that is Matrix coated and contoured to offer complete contact with the handlebar to provide strength and optimize stress distribution. Another plus if you are using carbon bars. All bolts on the stem are constructed from titanium and have tapered heads.