Many bloodstain examiners find this type of magnifier helpful when measuring and analyzing bloodstains. It comes in two different sizes and power of magnification. Both magnifiers have easy-to-read, built-in scales and large lenses for easy viewing. It comes in two different power, 5x and 10x. The larger 5x magnifier has a 60mm metric scale built into the base for easy measuring of large bloodstain areas, while the smaller magnifier has a powerful 10x lens for close-up examinations of bloodspatter trails. The larger unit has a 2 1/2" diameter double glass lens and has a 4" diameter base, while the smaller unit has a 1" diameter lens and a 1 3/4" base. The transparent acrylic base on these magnifiers allows ambient light to illuminate the bloodstain or other physical evidence being observed.