The Aven Tools 26200B-209 E-Arm Focus Mount with Integrated LED Ring Light and Brightness Controller is 74mm diameter with coarse focus. This model is used for SSZ, SPZ, DSZ and NSW series microscopes.Includes a built in eco friendly daylight 60 LED ring light with dimmer control. LED lights have a long life and low power consumption. Designed to fit Aven's Binocular and Trinocular stereo zoom microscopes. 60 ultra-bright, energy efficient LEDs provide a minimum of 20,000 hours of high output life. Comes complete with a dimmer control.