2pc 300mm x 30mm TCT circular saw blades 40 and 60 teeth with adapter ring TE517 5056133349139 | eBay
TOOLSTAR Saw Blade Adapter Bushing Washers, 3pcs Metal Circular Saw Blade Ring Reduction Bushing Adapters (32 x 25 mm) - - Amazon.com
16pcs Saw Blade Bushing Set Saw Blade Adapter Ring, Angle grinder inner aperture conversion gasket,1 Inch to 20 mm, 1 Inch to 5/8 Inch, 7/8 Inch to 5/8 Inch, 20 mmto 5/8 Inch,4 per Model - - Amazon.com