DID YOU KNOW?! The term 5X5 (pronounced Five By Five) is rooted in the communications within military forces through WWII to mean “I understand you perfectly.” 
The first number represented the Signal Strength of a radio communication, and the second number represented the signal clarity on a scale from 1-5 — 1 being the worst; 5 being the best. Therefore 5 x 5 means the signal has excellent strength and perfect clarity – the most understandable signal possible. Five by five is the predecessor to the term “Loud and Clear” It also found its way into verbal slang, meaning “everything is good” or “everybody is well/good”.