Where 2 get dump valve to replace cap on Seaquest D3?

[84CJ7]

I have a seaquest dimension D3 bcd that has cap instead of a dump valve on the rear lower port. Its an original cap since it says seaquest, but I don't know if this bcd has an overpressure valve anywhere and so I figure it would be nice to get one of those pull cord dump valves that is also an overpressure valve if anyone makes one that would fit on this type of port. The cap screws down onto a rubber ring so it looks like at one point there would have been an optional part to do just that.

 

[fishfood]

goto your local dive shop... mine has one in stock most of the times...
if they are a aqualung dealer they can order you one if they still make it in the size...