The light provided in the bonus items is meant not only to help view your samples brighter and clearer, but it also helps to change the angle of the microscope, so that the surface of the sample can be observed more in detail. The
reflection light from the top and the transmission light from the bottom - both make your observations more real and rewarding. The slide with the bulging portion in the center helps hold living/moving things in place and observe them with ease. Science guide included (68 color pages).