Featuring dual-mic Environmental Noise Cancellation (ENC) for use in loud environments, the Hollyland Solidcom C1 Pro-6S is a full-duplex wireless DECT intercom system engineered to provide clear audio and all-day wearing comfort in a true-wireless design with no bodypack or hub required. This configuration includes 6 single-sided headsets, 1 master and 5 remotes, along with rechargeable batteries, a charger, and accessories. The system transmits in the 1.9 GHz spectrum and uses proven DECT 6.0 technology to ensure secure and reliable transmission at a line-of-sight range of up to 1100'—making it well suited for a variety of applications including film/TV production, concerts, and live events.

Source: B&H
https://www.bhphotovideo.com/c/product/1751336-REG/hollyland_hollyland_solidcom_c1_pro_6s.html/overview