Switchable coupling

The clutch (1) a housing (2) comprising a compression area, and drive- and output elements rotatable against the housing. Clamping ramps are provided in the output elements and turned toward the compression area. Multiple clamping rollers are arranged between the compression area and the ramps. A collar (3) is connected with the drive element and movable in the housing along a career. The collar has contact surfaces for the rollers. A friction brake is designed as an open friction ring (4) that influences on the collar and is axially supported between the collar and the housing.