Features: 1Aluminum Alloy: Stereo microscope focus adjustment arm is made of high strength aluminum alloy material, not easy to bend or deform, long lasting. 2Size: Diameter of annular ring holding microscope head is 50mm / 2in, hand wheel focusing range is 95mm / 3.7in, fine adjustment accuracy is 0.02mm / 0.01in. 3Applicable Size: Stereo microscope focusing rack is suitable for 32mm/1.3in microscope column arm bracket, please confirm before purchasing. 4Wide Application: Microscope focusing bracket is widely used in microelectronics, molds, jewelry, printing, mobile phone repair, schools, etc. 5Simple Operation: Microscope ring arbor bracket is easy to install and disassemble, no complicated operations, convenient for using. Item Type: Stereo Microscope Head Holder Material: Aluminum Alloy Diameter: Approx. 50mm / 2in Hand Wheel Focusing Range: 95mm / 3.7in Fine Adjustment Accuracy: 0.02mm / 0.01in 1 x StereoMicroscopeHeadHolder