extruded U Channel which I screw to the studs and is just wide enough to slip the bench in place. Extra care needs to be taken with caulking and waterproofing.
the C-channel pulls, this panel-front built-in side-by-side is not trying to conceal its identity. The chalkboard panels are a nice alternative to stainless steel, alleviating fingerprint worries for the busy family who uses it.