Diy BEATS BY DRE Bluetooth helmet speakers system. Will work with most any helmet or speakers. | TY4stroke: Snowmobile Forum | Yamaha - 4 Stroke
$25 DIY Bluetooth Helmet Speakers : r/motorcycles
Amazon.com: I A S U S Premium Audio Motorcycle Helmet Speakers Work with Most Helmet Comms with Earbud Ports - The XSound 3 Drop in Helmet Headphones Speaker Kit Includes Accessories for a Quick Install : Electronics
Do it Yourself : Make a Helmet Headset Using Old Headphone - YouTube