Its a gasket. It fits. When installed, it doesnt seem to leak. I ordered, and Spruce shipped. Normally, I wouldnt be reviewing a gasket, but I have been getting insistent emails telling me that I need to review this order, so that I can help out my fellow aircraft maintainers. Like I said, its a gasket. Does the job. Easier than using an X-Acto knife to cut one out of gasket stock.