Fab International 6 Pack Oster/Osterizer Blender Blade Sealing Ring Gaskets Made from food grade Silicone Rubber. This is an after market product and not an OEM product.It is possible that it may not fit every model. Buyer pays for all return shipping. For all Undeliverable orders the sale will be treated as complete Will Be shipped in a white envelope without tracking no. via USPS First Class. With a black stamp saying "Your Amazon Order."Or maybe shipped in a Zip Lock Bag. OD 65 mm, ID 50 mm approximately.