Super Heavy Duty

Super-Heavy-Duty
A zinc–carbon battery (or “heavy duty”) is a battery packaged in a zinc can that serves as both a container and negative terminal. The electrolyte used is a paste of zinc chloride and ammonium chloride dissolved in water. Zinc–carbon batteries are the least expensive primary batteries and thus a popular choice by manufacturers when devices are sold with batteries included. They are commonly labelled as general purpose batteries. (Wikipedia)