To fit Black & Decker Reflex Plus twin line grass trimmers. Suitable for: Reflex Plus machines (twin line models) GL315, GL337/SB, GL350, GL500, GL546SC, GL600, GL650/SBC, GL651SB, GL652, GL653, GL655, GL656, GL660PC/SPC, GL670PC/SPC, GL675, GL680, GL685, GL686, GL687, GL690. Grass Hog GH600 (twin). Compares to A6441, 597862-00, 575462-00.