SRAM X0 9-Speed Rear Derailleur - The Bicycle Planet | Long Island, NY
Mountain Bike Rear Derailleur 7/8/9/10/11 Speed MTB Road Bike Rear Derailleur | eBay
MTB M4000 9 Speed Mountain Bike Rear Derailleurs 9/27 Speed RD-M4000 Bicycle Rear Derailleur Shifting Cycling Parts
Amazon.com : Box Two Prime 9 X-Wide Rear Derailleur Bicycles MTB Hanger Non-Direct Mount for Mountain Bike, Cycling Finished Gloss Hard Onyx Sealed Bushings Pulleys | Black : Sports & Outdoors
Will my bike frame be compatible with a 9-speed derailleur? (more in comments) : r/bikewrench