I'm unsure, I think it's custom or something vintage (both).
No one uses mercury any more as a working fluid in the pump. you use vacuum rated oil instead. And he's definitely using mercury. Also looks like a two stage piston pump. And mostly people use liquid ring vacuum pumps as roughing pumps.
Difficulty the roughing pump only gets you to a few microns at best. Good enough for neon work. But tubes require a hard vacuum. Need a diffusion pump (hot oil vapor) or turbo molecular pump (ultra high speed 'fan') after the roughing pump.
I don't think he's using a diffusion pump or turbo molecular pump.
