This Jodon 3.39 um (IR) HeNe Laser has a bore diameter of 5.5 mm and a beam diameter of 4.52 mm. The recommended discharge current is 96 mA (!!) and its maximum power output is 25 mW.
This laser head is BIG and HEAVY. It measures over six feet long and weighs well over 200 pounds. A similar laser in new condition goes for over $17,000. From the appearance, it is highly likely that the tube in this sample is very gassy or up to air.
This is a wide bore (relative to the normal 632.8 nm wavelength) laser. Note that a similar size tube at the 632.8 nm red HeNe wavelength would probably have 50 to 100 mW and would use zillions of magnets alongside the tube's bore to suppress the IR lines (including the one at 3.39 um).
(The following 8 photos provided courtesy of: binoman (firstname.lastname@example.org).)
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