Abstract: A spool upon which one or more lengths of filament are wound is provided and housed within a cylindrical cover having one or more generally radial openings formed through one wall portion thereof and the free ends of the filaments are threaded through the openings and extend outwardly therefrom for flail-type cutting of vegetation thereby when the spool and housing are rotated as a single unit at high speed. The spool is controllably rotatable relative to the housing whereby the spool may be rotated in discrete controllable increments in a direction to unwind the filaments therefrom so as to renew the extended end portions of the filaments projecting outwardly of the housing by said predetermined increments as the extended ends of the filaments incur breakage.