AgfaPhoto Heavy Duty 1.5V batteries are recommended for devices that are in everyday use. The world's first developed chemical power source was carbon-zinc batteries and they are still widely used due to their stable operation and low price. They can be used in many devices, for example calculators, alarm clocks, wall clocks, toys or even low-power flashlights. Heavy duty batteries are also called dry cells because they contain ammonium chloride in a dry, powdered form for safer use. Heavy duty batteries are non-rechargeable, discharged batteries must be collected only in designated containers.