Toy stores have just two words for you: slap bracelets.

"They are hot," says Vonnie Anderson of Lowen's Toys in Bethesda. "I got them in Friday afternoon and they were gone by the time we closed on Saturday." She estimates she sold 144. Once a week she reorders.

"We've gone through so many of those, I can't even remember how many I've reordered," laughs Elizabeth Gutekunst, manager of the Red Balloon in Georgetown. "When people come in, they buy five. I just sold four while I was talking to you."

The latest fad in the tradition of Teenage Mutant Ninja Turtles and last year's crazy glasses that were drinking straws happens to be a slight-looking bracelet -- a nine-inch piece of metal encased in brightly patterned fabric. Slap the metal against your wrist and it wraps itself around your arm.

Six-year-olds and 12-year-olds are wearing them. Girls and boys.

"Everyone at my school has them," says Rumal Rackley, a 13-year-old eighth-grader at Sidwell Friends and the son of Mayor Marion Barry's press secretary, Lurma Rackley. "They're like watches, that's how popular they are." Rumal himself doesn't have one. "It seems like they'll break too easily," he says.

They're so hot they've become dangerous. In Connecticut the metal in one off-brand slap bracelet slipped out of its fabric sheath and cut a 4-year-old's finger. In Pelham, N.Y., elementary school officials banned the wraps out of concern that children would cut themselves. Since then Connecticut's Department of Consumer Protection has declared that only the original Slap Wraps bracelet from Main Street Toy in Simsbury, Conn., is safe. The company figures its prototype was copied by shameless imitators at the New York toy fair last February.

"I've just stopped selling them to anyone who's going to give them to anyone under 8," says Donna Sullivan, owner of Sullivan's Toy Store on Wisconsin Avenue, which is also experiencing a run on them.

"We have on the tags '8 and up,' but typically kids that are 6 and 7 are going to use it," says Main Street Toy comptroller Tim Smith, father of 4- and 6-year-old boys and an 8-year-old girl. "My little guy has a harder time getting it around his wrist."

Florida inventor Stuart Anders brought his slap bracelet a year ago to Main Street Toy President Eugene Murtha. "When this person showed up with this product and he slapped it on another person's wrist, they smiled," says Smith. "And {Murtha} knew when the person smiled, this is going to be great. And it makes a certain click, a certain slap."

"There's an old philosophy in the toy business," explains Deb Baker, vice president of marketing for Main Street Toy. "If it makes you laugh out loud or smile, chances are it's going to be okay."

And it was different. "Gene and I both felt the product had a lot of potential from the fashion end as well as the toy end," Baker says. "You can do something with it."

It was a modest investment for the small two-year-old toy company -- "We're refugees from Coleco," says comptroller Smith -- as well as for the buyer.

"What's nice is that it's a fad that's pretty much affordable to everyone," says Sullivan. "Koosh balls were wonderful," she says of the $4.99 soft balls that look like rubbery porcupines, which were popular last year, "but I don't think every child saving their allowance could afford one."

The Slap Wraps retail for $1.99 to $2.49. "Ours is made of a high-grade stainless steel," says Smith. "It's rounded on the edges like a tongue depressor. And it's a tight fit. It doesn't fray because it's double-woven fabric and heat-sealed."

Many of the bracelets being slapped up around town may be the knockoffs, which generally sell for $1 to $1.50. But even with the presence of these imitators, Main Street Toy estimates that by the end of this year it will have shipped 4 to 5 million slap bracelets (which bear a label reading "Slap Wraps by Main Street Toy"). And it's only been shipping them since late summer, mostly to the East Coast. It has yet to ship the bracelets west.

"I'll probably go tomorrow to get one," says 11-year-old Lisa Wagner, a sixth-grader at Horace Mann Elementary. "A lot of my friends have them. They're different. They're not like any other bracelets. There're so many other bracelets. They're fun to play with and you don't get really bored."