...."the iPod of getting baked"

They can look like nondescript writing pens or asthma inhalers. Some resemble lip-gloss sticks and come in the same hot pink or sparkly purple as teenage girls' smartphone cases.

Others are bullet-like cylinders hanging on fat gold neck chains like gangsta bling. Some come boxed in a rainbow of neon colors looking a lot like marking pens.

Portable pot vaporizers — called "vapes" or "pocket hookahs" by users — are going hand-in-hand with the proliferation of electronic cigarettes and taking the marijuana world by storm. They are so well disguised and can be used so clandestinely that they are setting off alarm bells with those concerned about keeping legalized pot out of the hands of minors.

"This is incredibly concerning," said Bob Doyle, executive director of the Colorado Tobacco Education and Prevention Alliance. "The marijuana vaporizing industry is as advanced or more advanced than the e-cigarette industry. The products are appealing to kids, and they promote the ability to hide marijuana use."

That is "absurd," said Mason Tvert, co-founder of Safer Alternative for Enjoyable Recreation. He said the vaporizers have been developed as a safer way for adults to consume marijuana without smoking it and without creating secondhand smoke.

"These products are not made, marketed or sold for kids," Tvert said.

A 31-year-old hardcore athlete and regular user of a pocket vaporizer, who asked that his name not be used, said he agrees with Tvert's assertion that vaporizers are meant as a safer alternative to smoking pot.

"I do it because it is more healthy," he said.

And more easy to disguise, he added.

"If you have ever tried to smoke on a chairlift while skiing, you can appreciate a good hand-held vaporizer. They draw little attention, are fairly odorless and work despite gale-force winds," he said.

The pocket vaporizers are made up of an atomizer and a battery unit that acts as a heater to create a breathable vapor. The batteries are charged with small wall plug-ins.

The fact that the vaporizers are tiny electronic devices with chargers like those used for other popular electronic devices prompted Rolling Stone magazine, in its June issue, to refer to them as "the iPod of getting baked."