Specification:Working Stroke: 50mm/1.97inLens Body Aperture: 76mm/2.9inColumn Diameter: 32mm/1.26inCenter Distance: 155mm/6.1inConnecting Diameter: 16mm/0.63inNote:As different computers display colors differently, the color of the actual item may vary slightly from the above images. Features: It is made of premium material,durable and has long service life. It is stable and has great performance while using. It can hold the microscopic lens tightly and steady. You can discretionarily change the focal length through the bracket.