Compatibility: Converts a multi-speed hub to a single-speed wheel. Works with all Shimano or SRAM 7 to 11 speed cassette-type hubs, for both mountain and road bikes. Note: This product does not convert the hub into a fixed-gear (fixie) setup; the hub remains a freewheel type. High-quality stainless steel: The sprocket is made of high-resistant stainless steel with strength and hardness twice that of standard 316 stainless steel. Hardness reaches 18 degrees. Chain compatibility: Designed for chain widths from 1/2" x 3/32" to 1/2" x 11/128". Compatible with 7-speed to 11-speed chains. Original chain can be used. Multiple sprocket tooth options allow for an optimal gear ratio. Specifications: Material: Stainless steel Color: Silver Teeth options: 12T, 13T, 14T, 15T, 16T (optional) Processing technology: CNC cutting Packing size: Approximately 12 x 8 x 2 cm (4.72 x 3.15 x 0.79 in) Application: Converts multi-speed mountain or road bike hubs to single speed. Compatible with 7, 8, 9, 10, and 11-speed chains. Package includes: 1 x Single-Speed Bike Freewheel Note: No retail packaging included. Please allow 0–1 cm error due to manual measurement. Ensure you are comfortable with this before purchasing. Due to differences in monitor displays, the actual color may vary slightly from the image. Thank you!