I spent a good 2 hours last night researching what this patch was for and it turns out that it’s for the 501st Military Intelligence Brigade. Which was active during the Korean war. Nice little historic tidbit. (Taken with instagram)
Worn from: 29 December 1986 - Current.
The key is symbolic of authority and control and alludes to security. The lightning flashes are symbolic of worldwide electrical communications, and the double-warded key, conjoined with the two lightning flashes, symbolizes military intelligence and security command united.