I started on the 717 using a DC Pro-X, but didn't really see the value of burning up batteries for one ears worth of ANR. Went to the Telex Airman 8, its a good option. Hopefully the hot mic function is used widely on the fleet, but it sure doesn't seem to be rolling out with any speed. In some cases I've seen where the observer panel has the hot mic mod, but not the CA or FO panel...