There are many things strapped and stitched onto a soldier's uniforms. They all have purpose and meaning.
So, how about those patches on the shoulders of the uniform? Jack Murphy, a former member of the U.S. Special Operations Command who helped start the site The Loadout Room, writes in a recent post these patches are more specifically called "callsign patchs." The Loadout room is part of the larger site SOFREP, which stands for "special operations forces situation report" and touts itself as the "number one site for authentic, accurate, and timely information related to the US and Allied Special Operations Community."
Murphy says they identify to others who you are and what you do and are used over radio. He also notes the Velcro on the front and back so "it can be turned over and stuck to your uniform sleeve without exposing your callsign in the chowhall or wherever else."
Here's more on what the above patches stand for:
I think you can figure out the one on the bottom. The three stripes signify what battalion I was in, 3rd Ranger Battalion and SNP of course is short for Sniper. Later on the Regiment had a new Callsign SOP which is what you see on the middle patch. I’m pretty sure they’ve moved on once again to something new, but I will hold off decoding this one for now.
The top patch is the one I wore when I was the Senior Weapons Sergeant on my Special Forces ODA. 1=the first company in my battalion or Alpha Company. 4=the 4th ODA in my company, the 4th team being the HALO team. B=my MOS, 18B or Special Forces Weapons Sergeant. Finally 1=Senior position. A 2 would be the junior position for that MOS. This was an internal callsign SOP to my ODA.
And there you have it. If you didn't know what a callsign patch was before. You do now.