It certainly isn't uncommon for motorcycle enthusiasts to own more than one helmet. After all, you could consider your helmet as a fashion accessory meant to complement your motorcycle. So, if you have more than one bike, chances are you have a several lids to match. Folks who commute on a daily basis would certainly benefit from multiple helmets, too, as there will come a point wherein one of their helmets will be out of commission in the wash.
Having multiple helmets is one thing, but having multiple communicators, especially expensive ones like Cardo's PackTalk models can certainly be downright impractical. Yes, you can purchase an Audio Kit for a secondary helmet, however, it misses out on the fancy JBL speaker system. Based on my personal experience, the standard JBL speakers offer far superior audio quality versus the non-branded speakers found in the Audio Kit. Having said that, Cardo has finally come up with a solution in the form of the PackTalk Second Helmet Kit.
The Cardo PackTalk Second Helmet Kit is similar to the existing Audio Kit, but comes with premium speakers by JBL. More specifically, it uses the same 40mm JBL high-definition loudspeakers which come as-standard when you buy a PackTalk communicator. Apart from the speakers, the Second Helmet Kit comes with multiple mounting options for various helmets. You can make use of either the clip-on attachment, or the Glue Plate which mounts to the side of your helmet.
The PackTalk Second Helmet Kit comes with two microphone options, again, making it compatible with all sorts of helmets. The standard wired mic works best for full-face lids, while the boom mic is compatible with open-face or modular helmets. It's compatible with all PackTalk, PackTalk Bold, and PackTalk Black models, and retails for $119.95. It's currently open for pre-order on Cardo's website, and will begin deliveries starting December, 2021.
Sources: Motorrad Online, Cardo Systems