SIZE: diameter 12"(305mm), Bend 2T, 4mm Thickness, Arbor 1". Arbor 1" with 7/8"-20mm-5/8" circular adaptor washer. UNIVERSAL FIT For Circular Arbor. For all circular arbor equipment brand. SK-5 steel is estimated to last 10x longer life than normal Carbon Steel. Please note that this saw blade is designed with a not very sharp edge, the blade is designed to use a higher weight with a higher roating speed and a less sharp edge to cut bushes. No need to re-sharp the blade before use. Warning: this blade use for heavy duty working, please use on more than 30cc equipment, It is best to use it on a higher than 50CC.