It's the same tube made by REO back in the day.
The REO LSTP.
It's a semi-standard tube with just the right gas fill, and pressure, to allow for lasing of all 5 standard lines between 543.5 - 632.8 (543.5, 594.1, 604.6, 611.8, and 632.8).
Sometimes you can get some stray raman lines, but they aren't advertised as being included. Similar to getting a multiline tube.
It's got a broadband OC on one end, and on the other you will find a littrow prism/HR coated broadband as well.
As you would expect from a regular prism, this prism also diffracts the light and places all the wavelengths in their correlating places of the spectrum. However, one face of this prism is coated HR broadband, so once this light is enters the prism and diffracts, it is also being reflected back through the tube.
The tuning takes place when this prism undergoes very precise rotation. By rotating the prism, you are allowing individual lines to resonate, thus gaining, throughout the cavity. Whereas the other 4 (or however many other lines remain) will collide with the bore walls and not have the opportunity to gain, thus no lasing will take place on these lines.
Very ingenious design, and is very similar on concept to other tuning designs. Whether it's an intra-cavity prism with external HR, or a littrow grating, they all work on the same principles.
It's on my must-have list, but not for a while. Aryntha has one, as Sam is selling a couple. A healthy one for $3k, and a couple others for a few hundred less that are either missing green, or have a long warmup, etc. I will eventually knuckle down and save for a few months to get one. Though it is not a pressing need currently.
As far as production, REO I believe still does it. As it's their laser, and you can still purchase it from their website. These are used in spectroscopy. When you need a laser capable of producing wavelengths over a tunable range, this is a fine option. It provides stable wavelengths, that change by fractions, of a fraction of a nm over warmup. These are used when you need to test a materials ability to absorb wavelengths, for instance in cavity ring down spectroscopy.
This is a science involving an external cavity using a Herriott Cell. This cavity resonates light within it in a ring-like patter. This external cavity is a vacuum sealed environment, with mirrors on both sides. One mirror has a hole in it for light to enter, and exit, and both mirrors are highly reflective.
This tube has a known spectral readout, as far as how it absorbs various wavelengths. They also know how long it takes for a pulse of light, at a certain power, to dissipate to nothing within the tube. How many resonations. When a gas is placed in the tube, they fire the laser pulse, and measure the new rate. They use this integer to identify the spectral qualities of various gases, and the rate at which they absorb various wavelengths.
Helium-Neon lasers are known to be used in this fashion, and I'd even put money on companies using this very laser.
