nolva or letro?

i dont understand the difference...
do they both just work as anti e's?

now i will be cycling test e only @ 500mg a week for my first cycle..

i think i will be prone to gyno as i already have somewhat fatty deposits under my nips..

i know to run nolva @ 20mg ED with pct, but throughout the cycle, which one is better?????

thanks bros

with a test e only cycle i would run 10mg/nolva ed thruout the cycle. i run letro if i'm taking tren/deca with test. also letro will b good to run if u dont want any water retention