When evaluating soft armor, the primary focus must be on the NIJ (National Institute of Justice) Standard 0101.06. You should prioritize Level IIA, II, or IIIA depending on the threat profile, with Level IIIA being the most common for B2B procurement as it stops most handgun rounds. Key materials to look for include UHMWPE (Ultra-High Molecular Weight Polyethylene) for its lightweight properties and moisture resistance, or Para-aramid fibers (like Kevlar or Twaron) for superior heat resistance. Ensure the Areal Density is optimized to balance protection with wearer mobility, and verify that the Backface Deformation (BFD) is consistently under 44mm during testing.