Nitrous Oxide - Blow down tube fitting?

I bought a used Nitrous Outlet blow down tube (with quick release) a few weeks ago. What fitting do I need to get to fit it into the accessory port of my NOS bottle valve?

accessory port? dont blow down tubes attach to the burst disk?

You take out the plug on the side of the valve and the burst disc is inside...

You take out the plug on the side of the valve and the burst disc is inside...

Can you explain this a little more I may just be dense though:)

I'll get a picture of what I have going on.

It depends on what valve is in your NOS bottle. They have changed designs over the years. Can you post a picture of your bottle and I will give you a link to what you need.
Dave