This is a 0.5X C-mount lens adapter for microscope video, camera or other accessories. It comes with a 28mm mounting thread and 0.5X reduction lens. It fits AmScope SM and SW series stereo microscopes. Features & Specifications : Power: 0.5X Mounting Size on Camera Side: 1" (25.4mm) in diameter Mounting Size on Microscope Side: 1-1/8" (28mm) in diameter Compatibility: SM and SW Series Stereo Microscopes Manufactured under ISO 9001 Quality Control Standards Warranty: 1 Year