Mountain bike groupsets: everything you need to know - BikeRadar
New Sram X-9 X9 2/3x10-speed Mountain Groupset Group Set White Lockout Type 2 Derailleur, Crankset, Cassette, Shifters, Chain - Bicycle Derailleur - AliExpress
Sunrace CSM990 9Speed Cassette X9 Chain Cogs 11-40T Mountain Bike Freewheel Wide Ratio MTB Freewheel Adapter fit Shimano SRAM _ - AliExpress Mobile
SRAM X9 9-Speed Rear Derailleur (Long-cage) - City Bikes