The H+Son SL42 700c (black msw) is the original 42mm high rim that took over a year to develop. Like the Formation Face, SL42 owes its stiffness and aerodynamics to 42mm profile height.
The two models share the same lightness, reduced to around 615 grams (plus or minus 15 grams) using the G609 aluminium alloy which is also 30 percent stronger than the 6061 aluminium alloy used in standard rim manufacture. SL42 features a machined side wall for use with rim brakes.