The BreathKey Model s100 breathalyzer is as slim as a smartphone. Unlike other bulky breathalyzers, it slips easily into your pocket or purse so that you can take it with you wherever you go. And there is no need to carry mouthpieces because there is no direct mouth contact when you take a test. It has a large backlit display with simple plain English prompts. One button operation gives results in seconds. Comes with its own leatherette pouch.