Qualified to BS9520 G0003 and BS9522 F0039.  They meet the requirements of MIL-C-38999 series 3, which is a  development of the earlier D38999 series to enable its use in a wider scope of defence applications other than Aerospace.  Grounding comes as standard and the connectors are 100% scoop proof.  Unlike the other series, coupling is by a metal to metal, self locking, triple start coarse acme thread.  This improves the EMC shielding, giving a 65dBs attenuation at 100GHz.