A cutting head assembly (100, 200, 300), a trimmer head and a power tool including such cutting head assembly (100, 200, 300). The cutting head assembly (100, 200, 300) comprises a spool (140, 240, 340) and an enclosure (180, 280, 380) combined to define a spool cavity arranged to accommodate a trimmer line (120, 220) wound on the spool (140, 240, 340), characterized in that the trimmer line (120, 220) is arranged to form a single layer of winding when being retracted within the enclosure (180, 280, 380).
