[c-shadow]

I meant key mapping and IR vs RF key availability. Back when MX3(M) was new model, there were 3 different models with very similar design and key layout, but some were unable to map a lot of keys. On some models the mouse function could not be turned off completely but would come back after a resume from sleep. Fortunately, my MX3-M allows me to turn off mouse, it turns back on only if I pull the batteries out.
One of the cons of old MX3-M is that 4 colored keys work only in IR mode. How does it work with T3?
Did you buy the version with microphone or without?
My old MX3-M also has some mic but I never found any use for it.