D batteries are a common type of ‘dry cell’ battery. These are the interchangeable models that are widely used in electronic and household devices. Dry cell batteries are distinguished from more specialised ‘wet cell’ batteries, which, as the name implies, contain liquid.
What does a D size battery resemble? They are typically squat and solid, with a barrel-like shape. Each battery’s positive contact point or terminal has a distinct metal cap shape.
In 1898, D batteries were invented. They are now also known as R20s, after the International Electrotechnical Commission designated them as such (IEC).