Evolv claims they have signatures of "all" the weapons in the world, but IPVM testing, plus information obtained via a public records request, shows Evolv routinely misses non-ferrous weapons.
In this report, IPVM describes its operational exercise of Evolv's non-ferrous detection.
Evolv Says It Can Detect "All" Weapons
Evolv describes its system as a "weapon detector" that can detect "all" the weapons in the world including Evolv's CEO declaring that they detect "all the guns, all the bombs":
IPVM's Operational Exercise