Husqvarna 966674401 T25 Tap Advance String Trimmer Head Genuine OEM Husqvarna part Replaces 531300371, 531301123, and 537338304 Fits Husqvarna 123L, 125L, 125LD, 125R, 128L and 223L Contains .095" Titanium Force trimmer line For 10mm straight shaft trimmers only