The SunRace MZ90 is a fantastic sci-fi take on the modern '1X' derailleur. It is an essay in swirling curved surfaces and light glinting off the edges between them. The whole composition is highlit using a colour pallette including several shades of silver/grey and SunRace's signature gold detailing. H. R. Giger would have loved it - if the Alien had decided to pursue Sigourney Weaver on a bicycle, this is the derailleur it would have chosen.
Technically the SunRace MZ90 is constructed from forged aluminium with a composite p-knuckle and cable roller assembly and a carbon outer pulley cage plate. As is the fashion of the moment, it has a switchable clutch. In a nod to keeping the weight under some kind of control, it has an aluminium hanger bolt, titanium small parts and dramatically cutaway sealed-bearing pulleys.
It's an original and stylish object - I am just not sure that I would want to risk bashing it on a rock. Somehow, it looks too precious and fragile for off-road use - but appearances can be deceptive.