A trimmer head housing having a first part and a second part. The first and second housing parts are configured to be changed between: a) a first state wherein the first and second housing parts are separated from each other； and b) a second state wherein the housing parts are operatively connected to be movable together around an operating axis. The operatively connected housing parts are configured to support at least one cutting component that is configured to effect cutting as the operatively connected housing pars are turned around the operating axis. The trimmer head housing has interacting parts cooperating between the first and second housing parts and configured to allow the first and second housing parts to be operatively connected with the first and second housing parts in only a single angular relationship with respect to the operating axis.
