Size: 5.1*1.5*1 cm. Material: Aluminum Alloy. Color: Black, Red. Recommended Torque Value: 15-20N.m. Package includes 1pc Bicycle Rear Derailleur Hanger. Compatible with mountain 40/42/46/50/52T and highway 34/36/40/42T. Features: rear derailleur extension, expands flywheel speed change, durable aluminum alloy material, and great accessory for cycling enthusiasts.