Binospec is a high throughput, 370 to 1000 nm, imaging spectrograph that addresses two adjacent 8 by 15 fields of view. Binospec was commissioned in late 2017 at the f/5 focus of the 6.5m MMT and is now available to all MMT observers. Aperture masks cut from stainless steel with a laser cutter are used to define the entrance apertures that range from 15 long slits to hundreds of 2 slitlets. System throughputs, including the MMTs mirrors and the f/5 wide-field corrector peak at ~30%. Three reflection gratings, duplicated for the two beams, provide resolutions ($lambda$/$Delta lambda$) between 1300 and $>$5000 with a 1 wide slit. Two through-the-mask guiders are used for target acquisition, mask alignment, guiding, and precision offsets. A full-time Shack-Hartmann wave front sensor allows continuous adjustment of primary mirror support forces, telescope collimation and focus. Active flexure control maintains spectrograph alignment and focus under varying gravity and thermal conditions.
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