RECTANGULAR BLOCK || Rectangular block made from imported optical glass with optically worked surfaces. All angles accurately worked with edges slightly beveled. Bubble free glass 3" LENGTH || Block measures 3" long, 1.5" wide and is 0.7" thick PHYSICS EXPERIMENTS || Excellent for physics classrooms. Ideal for a variety of experiments in refraction and reflection PHOTOGRAPHY || Great for photography lighting and distortion effects MANUFACTURED BY EISCO LABS || Eisco Labs proudly manufactures its own products using state-of-the-art equipment, and following the highest standards of quality control. Each product is carefully designed by a team of laboratory professionals and experienced engineers with quality and durability in mind