Just to see if it works?
Battery-powered intercom http://www.aircraftspruce.com/pages/av/intercoms_0browse/acs_skycom.php
That's a funny way of spelling Halos.just buy the Zulus.
Actually I always encourage guys to pay attention to noise cancelling without the ANR powered on. Passive noise reduction is important. Find a couple you prefer and then compare them with the ANR turned on. Off. On. Then buy the Zulus.
Same with me. And one of the best $7.00 aviation gadgets in my flight bag is this Storacell battery holder. (Amazon.com Link)Altho some here will complain about losing the ANR when the batteries die, never bothered me because I always have a spare set or two of batteries with me.