What part of an Atomiswave cab is this?

Seller of the cab told the buyer it's for buttons 5 and 6 but never said where it plugs into exactly. I don't know much at all about AW cabs.

There are a couple of ways to get button 5 & 6 on these cabs. This link explains the plugs and their pinouts. This plug looks like the male end of the X plug.

The way I have it setup is all 6 buttons are plugged into the J & K connectors. 4 & 5 are wired to the jamma harness and 6 goes to a small plug in the bottom of the cab labeled S. I have a jamma adapter that breaks out 4 & 5 to a cps2 kick harness, then s plugs into 6th button of cps2 kick harness.

I can post some pics if needed when i get home from work.