Iridium RST755 Privacy HandsetThe RST755 Privacy Handset is an optional accessory for the 9555 IntelliDOCK for added convenience with auto sensing answer and hang up intelligence.Features:Enable privacy callsAuto hand up on handset placemet back in cupAuto answer on handset removal from cupThis product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns.