There are two sizes of gaskets required for the 3+1/4inch Pre-WW1 Davison sight glass. A 31mm OD gasket to fit in the top cap and a 29mm OD gasket to fit on the base of the glass.
One Top gasket and one Base gasket should be installed.
In the kit there are 2x 2mm and 3mm thick gaskets (4 gaskets in total)
