This is another amazing prism!! It is 76mm long. I love to play with light and see how it travels, bends and seperates to show us what it is made of ....magnificent colors. I attatch a swivel so that you can fine tune the angle that the sun hits the prism for your optimal veiwing pleasure! I tried to take the background away in the last picture. I didn't do the greatest job but I think it helps to see the prism better.