United Scientific PAR100 Acrylic Right Angle Prism， 100mm Length， 25mm Right Angle Side， 35mm Hypotenuse<img src="http://ecx.images-amazon.com/images/I/31uVS7u7Y6L.jpg" noproxy><img src="http://ecx.images-amazon.com/images/I/21EzFrxI4zL.jpg" noproxy>