I need help identifying which Magsafe Power Adapter I need for my Macbook Pro Model A1398, EMC 2673?

See: Find the right power adapter and cord for your Mac notebook - Apple Support

Provided the computer-end fits, you are free to use one with a HIGHER Wattage rating. No damage whatsoever will be done to any component, but it will likely run cooler (but may be slightly heavier).

If you use one with too LOW a Wattage rating, you will not be able to charge and run at the same time, and your computer's top speed (for its most intensive computations) will be limited.