Hello Painterman67. Any current headset should work with your new gmax helmet. J&M, Chatter Box etc. make their units so they will fit a wide choice of helmets. I currently have Chatter Box headsets in my Shoei Modular and they tuck up inside nicely. You will need to order the 3/4 helmet style mic. The unit will mount on the side of the helmet and the mic boom will tuck up under the flip up portion of the helmet.
Greg