Esky 4 channel TX and RX are done specially for each.

I just found out that an Esky TX 0404 does not work well with a RX designed for and Esky 0406, although they function but helicopter will sway in many directions and only can be controlled by the pilot handling the sticks.
Note: now my Lama V3 can fly through the house corridor without a crash and is very stable (previous receiver antena removed in a learning accident and could not solder it exactly in the original location) Bought a new 4 in 1 esky receiver from AgeHobby(delivered from China in only 10 days) and saved some money ($40.10 including S&H).
Note: Old Esky 4 ch 72 Mhz (RX 4 in 1 for E012(no letter A)) do not work properly on newer TX 0404.