"8 Alternating layers of bullet proof and impact resistant material with heat proof mesh mean this vest will keep just about anything out."
R4 Guardian Vest is a vest made by Ronson which has very high thermal defense just like the rest of the set. It is the mainly-used vest for heavy armor because of its high defense on both Physical and Thermal defense. It is preferred more than Titan Teslashock because it has no movement penalty. Though it must be noted that it has a weaker acid defense than some armor at its level, it is still extremely good for when it appears, and the one shouldn't be dumped without checking what it does for you (unless you get one without Augment slots, then consider dumping it).