can someone ID this bottle nut?
 

I bought this adapter and gauge but it doesn't fit my NX bottle. j ust hopeing i can find out what it would it so i can find someone that might be able to trade me for a -4 an adapter ...

http://images.spankaveli.com/adapter1.jpg
http://images.spankaveli.com/adapter2.jpg
http://images.spankaveli.com/adapter3.jpg

Thanks in advance.