Pip-Boy medical enhancer

The Pip Boy Medical Enhancer consists of a storage holodisk, microfilament cord, headgear, and an optical sensor that is placed over the user's left eye. When used, an optical flash transmits a dictionary of physician skills and know-how into the user's memory, permanently improving the user's doctor skill.

Location
This Enhancer is probably one of the most obscure items in the entire game. To get it, you'll need to steal the Spectacles from the Professor's radscorpion in Broken Hills and bring them to Renesco in New Reno. You'll have the opportunity to ask him for money, a discount on his wares, or to just let him keep them.

If you don't take a reward, you'll have the option to ask him how the glasses are working out. Do that 20 times, and you'll annoy him so much, he'll throw the Medical Enhancer at you!