The simple bottle cap has been elevated to middle-school must-have. At the age of 10, Maddie Bradshaw of Dallas decorated her first bottle cap, then attached it to a necklace cord with a magnet attached. Soon her friends were clamoring for their own.

Now 13 (!), Maddie manages the up-and-coming sensation known as Snap Caps, which lets girls swap out the bottle caps to suit their outfit and mood. Each necklace sells for $14-15, and you can buy bottle caps separately (perfect for decorating the inside of lockers, too). There are 13 collections, including “Diva,” “Candy,” and “Trends.”

To buy, go to M3 Girl Designs.com, let your kid select her fave, and e-mail m3girldesigns@yahoo.com.