There is a product that hundreds of millions of people use every single month.

It sits in medicine cabinets and under bathroom sinks across the world.

It is sold in every drugstore in the United States, in supermarkets and convenience stores, in countries on every inhabited continent.

The global market for it represents billions of dollars in annual sales.

Virtually every woman who has used it, and virtually every person who has sold it, bought it, stocked the shelf it sits on, or loaded the truck that delivered it, knows nothing about the woman who made it dramatically more useful.

Her name was Mary Beatrice Davidson Kenner.

She was a Black woman from Virginia who spent decades of her life inventing things — thinking through problems, designing solutions, filing patents, and waiting.

She was born in 1912 and died in 2006, which means she lived long enough to see herself recognized as a pioneer, though recognition came late and never reached the scale that her contributions deserved.

She held five patents during her lifetime, becoming the first African American woman to achieve that number — a record she held for many years.

At least one of her inventions was so fundamentally sound that the product category she improved went on to become a global industry standard.

She spent eighteen years trying to interest a company in manufacturing one of her most significant inventions before a company finally agreed — and then backed out when they discovered she was Black.

Eighteen years of waiting.

Followed by rejection based not on the quality of her design, but on the color of her skin.

And then she waited some more.

Mary Kenner eventually saw her invention manufactured and sold.

She eventually received recognition from institutions and organizations that sought to recover the history of Black American inventors.

Her name appears in encyclopedias and on lists of important African American historical figures.

There is a documentary made about her.