Our aerospace and defense customer needed NAS1352N04-06 socket head screws for their assembly but with a tamperproof pin-in socket head, which is not readily available off the shelf.  We had the pictured custom tamperproof version of this NAS1352 screw manufactured domestically to fully comply with the NAS specification using DFARS compliant material, with of-course the exception of the drive type.  Parts measured 4-40 X .375" and full certs were provided with the parts.