Arimidex=Strong Aromatase inhibitor: prevents conversion of test to estrogen
Femera=Very strong aromatase inhibitor
liquidex=liquid arimidex
nolvadex="anti estrogen" or Selective Estrogen Receptor Modulator competes with estrogen for place on estrogen receptor in breast tissue.
Pretty much, but femera is considerably more effective. Do a search, there was a post recently with attached research that even claimed .1mg of femera to be essentially as effective as 1mg Arimidex.