This reduction lens is designed to couple C-mount cameras with a microscope's ocular tube or photo tube. The male C-mount thread attaches to the camera, and the 23mm tube fits any standard ocular tube with a 23mm, 30mm, or 30.5mm diameter. The 0.37X magnification is ideal for cameras with a 1/3" format or similar sensor, optimizing the field-of-view and sensor coverage.