The Kisai Intoxicated Breathalyzer Watch gives you a digital read-out of your blood alcohol level and can tell you when it’s time to call a cab.

If your friends have told you one too many times that you’ve had one too many, there’s a watch for you.

With a quick twist of the flask-like cap, blowing into the side of the Kisai Intoxicated Breathalyzer Watch will give you a digital readout of your blood alcohol concentration (BAC).

For $149, you can get yourself a stainless steel, rechargeable drinking buddy who’ll accurately gauge when it’s time to call it a night.

The watch’s designer, Tokyoflash, says the device isn’t meant to be used as a safeguard to determine if you’ve had too much to drink before driving. They, like everyone else sharing the road, remind people that drinking and driving is never a good idea.

“It is relatively accurate and does not require calibration. It’s a fun watch design though, and we don’t advise people use it as a breathalyzer when considering driving,” Paul Cooper, spokesman for Tokyoflash Japan, said in an interview with Healthline. “In fact, we advise that people do not drink and drive under any circumstances. We regard the product as a fun watch that you can use with your friends to see how drunk you are.”

Tokyoflash is known for their unconventional watches, especially the way they display time using LED and LCD light technology. They’re always toying with ideas to make their watches more fun, useful, or interesting, and when an idea for a breathalyzer function was posted on their blog in June 2011, they ran with it.

The watch has been so popular that the first batch is already sold out. Right now, they’re on pre-order and should be shipping by July 8. Even if the watch doesn’t get to your wrist by the Fourth of July, it can help you and your friends track your BACs by Labor Day, with plenty of time to spare.

While the Intoxicated Breathalyzer Watch is the fashion accessory that screams problem drinker, it’s not going to keep you out of jail should the cops catch you Tokyo drifting home from the bar.

“I think it’s a good reminder and raises awareness of how much alcohol is in your system, but I don’t think anyone should drive after drinking alcohol, so this should not be used as a test before driving,” Cooper said. “It’s a fun watch and should be used as such—to have fun with friends and see who is most inebriated.”

After all, the “my watch told me I was OK to drive” defense probably won’t hold up in court.