Abstract: An automatic-deployment reel-type cutter head for a filament trimmer provides for manufacturing purposes an easy-wind structure and for operating purposes, a winding pre-selectivity of filament-deployment length from the cutter head. The cutter head structure also during cutting operations protects filament wound on it but not yet deployed. In a preferred embodiment the reel comprises a first circular member with an array of postlike elements upstanding from the rim and a second circular member for capping the free ends of the array of upstanding elements to prevent transient-load disarray of the filament during operation.