SING F LTD 20pcs Motorcycle M6 Rubber Grommets Set Fairing Cowling Pieces Buffer Washer Pressure Relief Cushion Universal for Most Motorbikes

if you have other one, get your callipers and measure it, with the actual dimensions it should be source-able. eg, https://www.amazon.com/SING-LTD-Motorcycle-Universal-Motorbikes/dp/B08SCCGMQR?nsdOptOutParam=true and, it's called a flanged bushing.