"Vest - Rated 7A for bullet proofness, explosives, cuts, stabs and impacts. Provides medium level protection from heat and toxic sources too."
The Special Forces Vest is probably the fourth vest the player will encounter along with the rest of the Special Forces Series of armor. It is the mainly used vest mid-game because of its higher stats compared to the Trooper Vest, without a punishing movement penalty. This vest, in its regular version, also beats the HVM Carbon Fibre Vest in all three categories of defense, and on top of that has no movement penalty at all and could possibly be effective until levels 30+ as you will find vests and the version of this at around 40+ (possibly at 35 from a nantonium).
The Special Forces Vest is most likely based off the Kevlar vests worn by policemen, explaining its high Physical defense.