0.4X C-mount Reduction Lens Adapter f/ Microscope CCD CMOS USB Camera 30 30.5 mm
Suit Microscope: biological microscope and stereo microscope. 0.4X magnification to get a more wide view of microscope. Mounting Size: 23.2 mm, or 30 mm, or 30.5 mm. You'd better take a video or photos when open it.