Merlin Lazer Glass and Glazing Analysis Equipment Set – Tempered, Air Gap, Low E. This is a professional grade glass testing set. Excellent condition. I used it about a dozen times. One tester checks to see if the glass is tempered, another tester checks to see if the glass is Low E, and the third tester measures glass thickness and air gaps in double and triple pane windows. I paid over $600 for these and they are pretty much like brand new with very little use. They come with a hard shell plastic carrying case with foam cutouts to keep the testers from moving around inside the case. Directions for each tester are included. Also includes a charger. There are a couple of minor scratches on the outside of the carrying case as shown in photo.