LANSING, Michigan — Jamie Mosley is a successful entrepreneur who's made a lot of money selling a product you might not have known there's a market for: e-cigarettes safe for jails.

Specifically, for his jail — or at least, that's how it started.

Mosley, a former state police officer who moonlights as a NASCAR driver, was elected jailer of Laurel County Kentucky in 2012. Without the option to sell tobacco in his commissary, the jail saw a new set of problems emerge, like withdrawal issues, inmate fighting, and an increase in black market trading of tobacco. Furthermore, Mosley found that corrections staff had one less privilege to take away from inmates to discourage bad behavior.

Mosley got the idea to introduce a vape option to his jail, but all of the ones on the market were too easily turned into weapons. So he invented a solution.

"Everything out there had a metal casing or was a very, very hard plastic and could be hammered down into a shank," Mosley told VICE News. "We also wanted something with a very low voltage so that you couldn't utilize it for an ignition source to start a fire with.

Crossbar, as Mosley calls his product, is now in some 33 prisons and jails across the county, and it's expected to do $3.5 million in sales this year. One Crossbar e-cig is said to be the equivalent of about two packs of cigarettes, but inmates say they're still essentially luxury items. Mosley's company sells the e-cigs to prisons and jails for about $2 to $3, and the facilities, in turn, sell them to inmates for between $10 and $15.

"When I developed the product, it was really not with the intention of starting a company. I was just trying to solve a problem within my own facility," Mosley added.