MR-150 posted:Can the couplers from the 800 series be used in the 700 series with the metal boxes
Do you mean will the 800 series couple OK with the 700 series? The answer is yes.
If you mean can the 800 series couplers be used in the metal gear boxes from the 700 series? The answer is yes, as ALL the metal gear boxes are the same, no matter whether from the 800 series or the 700 series.