Alivio RD-M3100 Rear Derailleur

Works well and great price!

It's stated as a 9-speed mtb rear derailleur but it will work just fine with 9 speed and 10 speed Shimano road shifters too because of pull ratios being the same (except the newest Tiagra 4700). Super easy to setup and has smooth shifting - stated cassette compatibility is 36t max but it can easily take 40t and possibly more depending the hanger/use of a hanger extender. Great price and shipping speed from Thunder Mountain Bikes!

Shimano Shadow

Great pickup, replacement derailleur for hard tail.