2.5"， 4"， 6" Amlong Crystal Optical Glass Triangular Prism for Teaching Light Spectrum Physics， Set of 3</br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br><img src='http://ecx.images-amazon.com/images/I/41s4Veu%2BSrL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/41IKJRyBMlL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/41nuR9whfBL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/41Mb4gHKJQL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/41pago3R7mL.jpg' noproxy></br>