The MAVIC 841 was the mid length derailleur in the MAVIC 840 series. It shared with its brothers the beautiful build quality, needle bearing pulley wheels, stainless steel pivots and fittings, Dura-Ace 7400 geometry and the ability to be completely disassembled (if you like circlips). Aside from the solid pulley cage plates (aerodynamic touring anyone?), it also shared the lack of MAVIC’s signature eccentricity (whisper it quietly in the presence of MAVIC aficionados - but I think Simplex may have played some part in its manufacture).
This mid length derailleur was vaguely interesting, as it was effectively a Dura-Ace capable of handling a triple (rather than a Deore XT), something that Shimano did not make at the time, and so was useful for cyclists who wanted to both pose as road racers and use a granny gear.