FSA's SL-K Stem was constructed to provide rigid support for the handlebars, feeling similar in both weight and stiffness to carbon and titanium with a precise, CNC-machined aluminum construction.
To guarantee rigidity, FSA 3D-forged the aluminum stem body. This process starts with one ingot of aluminum that is bored out and shaped internally. This improves the aluminum's grain structure and eliminates the use of welds for drastically reduced weight. The benefits to you are a heightened stiffness, with weight comparable to carbon fiber, at a considerably lower cost. To maintain the flow of weight savings, the SL-K uses a carbon fiber face plate with chrome-moly hardware.
The SL-K features a 40mm fork-clamp stack height with a 6 degree rise. FSA has included clamp-to-clamp model graphics that run inverse of each other to keep the aesthetic unchanged whether you slam the stem or run positive rise. It is only compatible with 1-1/8in steerer tubes and 31.8mm clamp diameter handlebars.