This is a high quality slide made especially for us here at Nature's Workshop Plus! This slide of Cycloid scale is used with the Marine Biology course by Apologia. Each slide is individually made, and will vary slightly from the one pictured here. The Cycloid scale pictured here is magnified at 40x. Our model #131 microscope was used to photograph this slide specimen. The black pointer near the top of this picture is a feature of this microscope, and is not a part of the slide.