Overall, this is a fun and nice product to have. I tried this before I had alcohol and it correctly said 0%. Then I drank a wine cooler and right after blew (and got the red mark in the product listing). I was surprised by this and tried it again a minute later and it was around 0.34%.... Therefore, I think it best to not use RIGHT after having a drink for a false high report. The instructions are easy to follow. I like that they have colors when it's completed (blue if under/low and red for high). I LOVE that it comes with its own batteries. The tubes that you breath into are also individually wrapped, so that is really nice from a sanitary viewpoint. It also comes with a little bag that you can easily hold it as well as some of the wrapped tubes you breath into. Pleased overall! Easy to use.
Want to check it out for yourself? Here is the product listing:
*disclaimer: I received this product in exchange for my honest and unbiased review. Opinions are 100% my own*