The NT-LS-HR01-A is a HeNe laser System with a maximum output power of 1mW. The beam is red in color (632.8nm) and the laser tube is a Hughes Melles Griot model 3121H-P-02-73 manufactured in March of 1990. The tube is contained along with the power supply in a small metal cage mounted to the base board. The power supply is a Power Technology Inc. model N017-1111 potted brick-style HeNe power supply. Since the laser power supply does not contain a current limiting circuit, an external current limiting board is contained within the control box mounted on the board as well. The control box accepts at least 12VDC and no more than 24VDC at the input lead. Power is switched directly by a key-switch mounted to the control box in an attempt to make the device CDRH compliant. The current limiting board is configured to output no more than ~12.2VDC at ~1.45A to the laser power supply. The laser power supply contained within the cage provides the necessary voltages to strike and sustain the HeNe laser tube.
Sam's Laser FAQ is a great resource for all things lasers. It proved to be very helpful in getting the HeNe laser tubes up and running.