Husqvarna T55X Strimmer Head\nThe largest strimmer head in the Husqvarna range recommended for machines 45cc and over Recommended line diameter 3-4mm Exclusively designed by Husqvarna the T55X trimmer head features a semi-automatic cord feed system \u201CTap\u2019n go\u201C Ball-bearing resting surface for improved durability Features developed for users with high demands on durability and minimized downtime The trimmer line is fed automatically when the head is pushed into the ground This means that the user always controls when the line is fed and the line can be fed while working with the machine Fits Models: - 343F 343FR, 343FRM, 343R, 345FR, 345FX, 345FXT, 345RX, 355FRM,355FX, 355FXT, 355RX 545FX, 545RXT, 553RS, 555FRM, 555FX, 555FXT, 555RXT Plus many other models Cord feed Semi-automatic For straight shaft trimmers YES Cord size 3 - 4 mm / 0.12 - 0.155 \"" Fits engine size +45cc Ball-bearing YES Thread M12 Inner diameter 1\"" \n\nHusqvarna T55X Strimmer Head\n\nThe largest strimmy