Marathon Special Products military terminal Blocks are available in materials type GPT-30F per MIL-M-24519 and GDI30F per MIL-M-14, color gray, and are Manufactured to the Military's newest specification A-A-59125 or still can be manufactured to Military Specifications MIL-T-55164 Military approvals (A-A-59125, or MIL-T-55164) are held by all Kulka military terminal blocks.