This string trimmer head spool retainer assembly is designed as a replacement part for a wide range of string trimmer models, ensuring compatibility and ease of installation; it fits PLT3043A, RLT30CD, PBC3046B, PBC3046E, PLT3043YE, PBC3046YB, PLT2543Y, PBC3020, PBC3020Y, RPT2543C, RBC254FC, RLT254FC, Expand-It, and many more; this kit includes one string head assembly, one right-hand spool retainer, one left-hand spool retainer, and a service card for easy reference; compatible with models 100r, 125r, 130r, 135r, 305-RT, 306-RT, 364-1, 500, 500-1, 700r, 700R-1, 710r, 720r, 740r, 746R, 750r, 760r, 764r, 765r, 766r, 768r, 770r, 840r, 920r, 960r, 970r, CS26 (RY28020), CS30 (RY26500, RY30000, RY30000A, RY30021A), IDC364, and various RY series trimmers; if your model isn't listed, contact us within 24 hours for assistance; this retainer assembly helps maintain proper spool tension and prevents string breakage, offering a reliable solution for your trimming needs; the durable construction ensures long-lasting performance and efficient operation; please carefully review the description and warnings before purchasing.