This is a 0.3X focus-adjustable C-mount camera adapter for our SM745NTP stereo microscope head. It comes with a 28mm mounting thread and 0.5X reduction lens. Features & Specifications : --Power: 0.3X --Mounting Size on Camera Side: 1" (25.4mm) in diameter --Mounting Size on Microscope Side: 1-1/8" (28mm) in diameter --Compatibility: SM745NTP (SM-3NTP, SM-4NTP) --Manufactured under ISO 9001 Quality Control Standards