(The following 6 photos provided courtesy of: Pendex Corporation.)
This is an Adkin (Advanced Kinetics) CO2 flowing gas laser - 50 W output. It consists of the laser head, reflow chiller (not shown), control electronics and power supply. The resonator has diffraction grating optics for specific line selection and includes a piezoelectric positioning system for the optics to allow for remote 'on the fly' selection of the laser line you wish. The laser head is model MIRL-50-SL, the power supply is model LPS-50, and the piezo controller is model PZT-2/3. Operates on 110/220VAC.
Since there are external line selecting optics, this laser uses Brewster windows on the end of the tube - not that common with CO2 lasers due to losses and large Brewster angle required for the window material (ZnSe?).