ZOOM C Mount Lens is mainly used in the following fields: Machine vision microscopic inspection Industrial testing, especially electronic component testing scientific research Education industry. 50X Zoom C Mount Lens(42 rings): Eyepiece lense: 0.5X Tips: The product may be updated constantly, The Actual Product May Have Slight Differences Or Color Differences the color and appearance may be changed, please don't mind. And take a consideration before place the order if you have request for color or appearance. Material: Metal colour: Black Package Contents: 1 x 50X high distance lens(42 rings) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.