8491AM Top Manifold Gasket for Halkey Roberts 840 Manual Inflator and V85000 Auto Inflator.
The 8491AM Top Manifold Gasket can be bought individually or in a multi pack. The multi pack listing can be found here.
This gasket fits between the inflator and the locking nut.
Anyone checking and fitting this part needs to have good technical knowledge of the product. This is typically a trade part used by lifejacket service stations and larger commercial users who have internal servicing.
Click here for information on the 840 Inflator.