That is a cool mod (for an ACE-x50). Since they are not waterproof anyway. I wouldn't do that to an AT-Pro personally. I guess the point is to get the headset cord behind your back ? He did a nice job on the mod. Bud
I think it's more of a mod that let's you use any 1/4" headphone with the Pro with added benefit of getting the cord out of the way of your hand. If your hunting in water you can just unscrew the headphone connector and install waterproof headphones in a couple of minutes.
Notice that there are no cords showing on the ATX Perry