UNIVERSAL FIT ***: ATIE blades fit any garden trimmer, brush cutter, weed eater that takes 1" (25.4mm) or 7/8" (20mm) arbor hole. Our blade is built for any RPM even super high RPM Trimmers (10,000+ rpm). The carbide tips are welded-brazed on and will not come off. Carbide is reputed to be one of the hardest-strongest alloys. Our carbide Tipped cutting blades are made with Tungsten or Titanium alloy. Buyer attention: Please refer to the owner’s manual of your trimmer / brush cutter / week eater and our product description to determine whether our blades will fit your tools. *** Note***: The arbor is the shaft, spindle or mandrel which the circular saw blade mounts to. The arbor hole (bore) is the hole in the middle of the blade. 1’ and 20 mm arbor holes are the most standard in the circular saw blade industry.