Product review (4 stars): A Must-Have For Freezers
A simple yet functional device implemented well.  After seeing this, I am wondering why something like this isn't built into fridges?  The concept is simple -- if the red ball has dropped, your fridge's temperature has risen above freezing.  How far the ball drops determines how long the temperate was too warm.  Of course, if the food has been exposed to warm temps too long, then the food could be unsafe to eat.  In such a case one wouldn't know if their food was at warm temperatures because often the power would come back on thus re-freezing the food.

Instructions were very clear.  The strap was also convenient, but in my case, it didn't work for my fridge because my fridge doesn't have wide bars like pictured on the product page.  It would be nice if the makers of this product figured out a solution that would work with more fridges.  For now, I had to prop the device against some food on a shelf.  Overall, I recommend this product and now consider it a must-have for any freezer.