Red Plastic 1/4" Inch Seal Gasket
Red plastic 1/4" inch seal gasket no idea what it's for! They are sold EACH.
As it's a very light item, maximise the saving on postage and buy some of the related parts below, or a new hose, and filters for your Nilfisk or ALTO vacuum cleaner, or a new floor tool and hose.
At the moment, postage is capped at $20!