Rac built-in FCS developed and produced TSFS (True Sound Field Situation) panoramic sound real-world sound processing and transparent transmission technology. After wearing it, it can clearly transmit the fine sound of any angle environment, and has the detail enhancement technology for some special sounds. It also has built-in SEO ( shooting environment optimization ) technology developed and produced by FCS. It automatically reduces the sound pressure of high sound pressure such as gunshots and explosion sounds. When it appears, it will automatically drop to a reasonable sound pressure level before it will be transmitted to the human auditory system. Tactical headset, built-in communication function for radio equipment, using U.S. standard communication interface U-174/U, can connect U94, RAC PTT and other PTT controllers (not compatible with original 3M PELTOR PTT). This feature works without a power supply. Price includes: 1 RAC headset and 1 Sand RAC U94 PPT and 1 K connection head (I have one more U92 PPT can connect with PRC-152 or 148) Ship fee $20