While named similarly to the pulse grenade and pulse rifle prototype, it is not actually an electromagnetic pulse weapon, but instead shoots electrical pulses effective against all targets, not just electronic devices. This is the most powerful single-shot weapon one can find in the game, next to the alien blaster. However, its hitting power is offset by its relatively short range and low ammunition capacity when compared to the likes of Gauss weapons. This gun is also less accurate than Gauss weapons due to the lack of ammunition modifiers.
Scoring a killing blow on an enemy by either a critical, Bloody Mess trait or simply a powerful attack will turn the enemy into dust. While this is no trouble for opponents that carry nothing, it is a source of great annoyance when trying to loot them; since there is no longer a body, the items which are scattered all over the ground, have to be picked up one by one. But it can be bypassed by turning the violence level down.
The YK42B, unlike the YK32 pulse pistol, doesn't fire a visible purple projectile. [verified]