Prism Loose Set in a box .This Instrument is used to diagnose the Binocular Vision of Eye to improve the accuracy Excellent for measuring:- Fusional Reserves – which can help in your diagnosis of binocular vision problems. Phorias Squints – which can improve the accuracy of your estimations monitoring. There are 11 Loose Prism in a box that is 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60. This are the powers of Prisms. Prism are fitted so accurately so that it will be easy to take and put. This is in wooden box which is weight is light and material is strong which will keep prism safe. The inner box color is red and outer color is black with suspicious look.