....or you can make one yourself. Parts stores carry flat bulk sheets of different types of gasket material that you can use.
Sometimes......a person might not have the time needed to get one ordered in.
Making a gasket should only take about ten minutes....put a light coat of oil on the housing, press the gasket material against it to get the shape and outline, then cut it out with a single-edge razor blade.
I grew up on a farm in Iowa. It was 17 miles to the nearest parts store. Made more than one gasket in my time.....