"We only have a few sets of these in stock, so do not miss out! These are the US Navy Vietnam era mask retention clips for the MS22001 and MBU-5/P oxygen mask. Known as the butterfly clips because of the ""wings"" you have to squeeze to release them. These mate with the chrome cutout horseshoe shape on your APH-6 series flight helmet. NSN: 1660-00-083-1502"
