Amazon with LavalesDirect has the Lavales 1Mii  SafeFly Pro Bluetooth 5.3 Transmitter Receiver on sale for $30 - 50% off with coupon code CN3TNJ6O at checkout (or clicking through the promo page) = $15 with free shipping on $35+ or with Prime. Lets you pair two headphones at the same time, 30 hour playtime.