Maybe you had to pick up some batteries for some of the presents you bought this month.

When it comes to toys, we’ve got AA, AAA, C and D batteries… but not B.

Why not?

Mental Floss took a closer look at the history of battery names, and found out that actually there are B size batteries, or at least there were.

The lettered batteries got their names in the 1920s.

Officials with the government and with big industries wanted to standardize batteries.

They wanted to have wide agreement on the sizes of certain batteries and what kind of output they should all offer.

For what are known as single-cell batteries, they decided to name them after letters of the alphabet.

The smallest was A, the next size up was B, and then C and D.

There was another large battery back then that was known as a No. 6 battery, and because it was already well known by that term, they decided to leave it in place.

Later, battery makers started producing single-cells that were smaller than the small A battery, so those became AA and AAA.

Those size batteries have been super useful powering lots of products, including consumer electronics, smoke detectors, and lots of toys.

And the C and D size batteries have been valuable in powering bigger stuff.

When I was growing up everybody had a pack of D batteries on hand so they could take their boom boxes around.

But the middle sizes, A and B in particular, just weren’t in high demand.

They were too big for the smaller products, and too small to power bigger things.

So at least in the U.S., they just didn’t catch on, so battery makers didn’t make them.

In Europe, there have been B batteries used for things like bicycle lamps, but these days those kinds of products are more likely to have lithium ion batteries like the ones in cell phones rather than the old school types.

So it’s likely people will continue to let the B batteries… be.

A few weeks back a research team demonstrated a “smart bandage.”

Their device not only monitors how a wound is healing in real time, it adds a little electric current that can help speed that healing process along.

Why Aren’t There B Batteries? (Mental Floss)

Wireless, closed-loop, smart bandage with integrated sensors and stimulators for advanced wound care and accelerated healing (Nature)

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Photo by Heather Kennedy via Flickr/Creative Commons