This is Echo's SRM Echomatic Trimmer Bump Head for Trimmers & Brushcutters (Trimmer Head Only) ** Fits ALL SRM Straight Shaft Trimmers! (Does NOT Fit Curved-Shaft Trimmers). ** Replaces OEM Part #'s: 21560050, 200095200 Fits the Following Echo Models: GT225, PAS-225, PAS-225VP, PAS-225VPB, SRM-1501, SRM225, SRM225SB, SRM-2301, SRM230SP, SRM-2310, SRM-2501, SRM-2510, SRM-265T, SRM266 series, SRM280, SRM-280, SRM-3000, SRM410U, 99944200470, 99944200545.