This is a 9" 4 tooth Archer Brush Cutter Trimmer Blade, this blade is designed for cutting grass and weeds. The blade has a 1" arbor but a 20mm adapter ring is included with the blade for installing on units with a 20mm arbor shaft such as Stihl. The blade is 1.8mm thick and is made of high carbon steel.
Archer products are sold world wide and are known for their high quality!!