A common practice at Sony : make something which is advertised at length for a host of available recorders... not available.
Or so little. If you're lucky.
Call me back next month.
Christmas perhaps ?
Next year then ?
The RM-50 is the optional wired remote control for the TC-K88B, TC-FX1010, TC-K80, TC-K77R, TC-K75, TC-K65, TC-K55, TC-K71, TC-FX6, TC-FX7, TC-FX600, TC-FX66, TC-K555, TC-K777, TC-V7, TC-YX7 - and ten or twenty others.
Most of these recorders sold like hotcakes, worldwide, but regarding the oh-so desired RM-50, that's... another story.
Like the TAC cabinets made for the ESPRIT series or the pretty enclosures made for TA-F55 / ST-J55 couple. They were made allright ! They were also advertised, yes. But why oh why, may I ask, would you want one ?
So -
Either you know the best friend's sister's cousin of the guy at distribution or you're an exec' at Sony. Or not.
Or not, or not, or not - repeat 50 times.