It's a gear box on a fractional horsepower drill press. Almost any oil will do the job.
If you really want to get fussy, auto transmission fluid might be ideal. Or 90w automotive gear oil, the yellow-metal friendly variety, also perfect. Available at any car parts store.
The Mobil 600 XP 150 oil you mention is for 24,000 horsepower marine transmissions, and 200hp mining conveyor belt drive boxes, perhaps a bit of overkill on the old drill press.
The ISO 150 grade is equivalent to SAE 90 gear oil, or straight 40 weight engine oil. Nothing exotic.
Edited By Hopper on 16/09/2016 12:08:00