The sink strainer gasket is located between the sink strainer and the garbage disposal mounting gasket. The gasket is used to create a watertight seal to prevent any water from leaking. Over time the gasket may become worm or damaged causing it to leak, and the gasket will need to be replaced. The gasket is black in color, made of rubber, and measures approximately 4 1/2” in diameter. Please remember to disconnect the power and water supply before starting your repair. This is a genuine OEM part.