It's a generic term for products such as PowerGel's, GU, Hammer Gel, etc... They usually come in a little tear-off pouch with around 1 ounce of gel. The gel is a concentrated, carbohydrate gel that delivers immediate energy and contains electrolytes. Each package is around 110 calories or so. Here's a link so you can see what I'm talking about.

http://www.powerbar.com/Products/PowerGel/

Dan.