Just added laser #400 to the Vintage Laser Archive (#325 without the multiples), and although it's not a really old one, it's special nonetheless. It's a 1992 Aerotech model 504R He-Ne with one unique feature. It's the only cylindrically shaped laser I've seen that plugs directly into main voltage. No separate power supply. No wall wart transformer, or charger for internal batteries. Just plug it in and lase.
I've been looking for a He-Ne like that for a long time. It completes the story of their development from RF excited meter long research device to plug-it-in light bulb. The following list are the He-Nes in the collection that show the 30-year evolution:
1. c1962 Spectra-Physics 110: First with visible beam.
2. c1963 Spectra-Physics 130B: First power supply in head, first with DC excitation.
3. c1963 Perkin-Elmer 5200: First with a cylindrical shaped head, first coaxial plasma tube.
4. c1966 Optics Technology Inc. 170: First visible-beam He-Ne with mirrors mounted on the tube.
5. c1967 University Laboratories 230: First coaxial tube with internal mirrors.
6. c1967 Spectra-Physics 122: First with the Hochuli cathode for long lifetime.
7. 1978 Bergen Expo Systems LP-6: First with side mounted momentary-on switch.
8. c1982 RMF Industries pointer: Battery operated.
9. c1985 Draper LP-5: Wall wart power supply.
10. 1985 Sentec SLP-201: Rechargeable batteries.
11. 1987 Aerotech 120R: Rechargeable or plug-in options.
12. 1992 Aerotech 504R: Direct plug-in with cylindrical housing.