You'd better make up your mind fast. Are you here to buy equipment, or did you just come here to get shot?
Zack is a diminutive shopkeeper of the Gun Runners in Fallout.
Owing to the industrial capabilities of the Gun Runners, Zack has access to vast stocks of high end weapons and ammunition available for purchase to anyone who can brave the Deathclaw hunting grounds near the Runners' Boneyard fortress.
Zack appears only in Fallout.