The Husqvarna T25 M10 semi-automatic trimmer head 578446001 is a powerful trimmer head that is suitable for use with curved shaft trimmers. It has an impressive feature called Tap'n go. This feature is a semi-automatic cord feed system. Therefore, this means that as a user, you can always regulate when the line is fed while you are working with the head trimmer. As long as the trimmer head is pushed into the ground, the trimmer line is fed automatically. Another advantage of this trimmer is that you do not have to turn off or release the machine from the harness while feeding is taking place. Specifications Curved shaft trimmers Cord feed system; semi-automatic Cord size range 2 to 2.4mm/0.08 to 0.95 inch The engine fits size thread 3/8 inch R Inner Diameter 1 inch Special features Open eyelet The open eyelet allows easy cord feeding of this trimmer head. This means that the cord feeding process is simple and easy to achieve. Exchangeable parts The parts of Husqvarna T25 M10 semi-automatic trimmer head 578446001 can be interchanged separately. Long-lasting With its advanced and upgraded material, the trimmer head assures you of a prolonged lifetime and reduced maintenance cost. Easy to use The Husqvarna T25 M10 semi-automatic trimmer heads are simple to attach, easy to load, and use. With Tap'n Go the line feeds while working automatically. Fits 122C, 128C, 129C.