Abstract: This invention relates to a boss assembly that seals a pressure vessel and more particularly to sealing a pressure vessel having a composite outer shell for use with a source of compressed gas having a boss and boss cover in sealing engagement. The composite outer shell is wound about the boss and locked into at least one notch and/or a reverse draft cut. The boss cover is removably fastened to the boss utilizing at least one fastener. The principle use is for storage and usage of compressed gas in mobile applications that typically benefit from light weight pressure vessels however other applications will benefit from this invention. For example, applications that routinely fill and/or un-fill containers made of woven, composite, and etc. materials will benefit from this invention.