Fallout: New Vegas implants

Talking to Doctor Usanagi reveals that she sells implants to augment your S.P.E.C.I.A.L. abilities, and two other implants, a sub-dermal implant that makes you more resistant to damage, and a implant that allows you to regenerate health. You can only apply a limited number of implants, the limit being determined by your endurance.

You get 1 implant for each point of BASE endurance. If you get an implant for Endurance, it will NOT allow you to get an extra implant. However, it is essentially "free" because it costs an endurance point but adds an endurance point. For example, if your starting endurance = 6, you can get 6 of the 9 possible implants. If you boost endurance to 7 with an implant, you still will only be able to get 6 total implants.

S.P.E.C.I.A.L. implants are 4,000 caps each. NEMEAN Sub Dermal Armor is 8,000 caps and adds 4 to your Damage Threshold. PHOENIX Monocyte Breeder is 12,000 caps and regenerates hitpoints at a similar rate to the Solar Powered Perk.