1,Outstanding Durability: Made from high strength steel material, this freewheel boasts high hardness, toughness, excellent wear proof performance, and rust resistance. 2,Versatile Gear Options: Featuring an 18 21 24T three speed design, this freewheel caters to various riding needs, providing a faster and smoother cycling experience. 3,Precise Compatibility: With English thread B1 3.75x24T, this 3 speed freewheel is specifically designed for spin hubs, making it an excellent cycling accessory. 4,Smoother Cycling: The cycle freewheel rotates gently, ensuring powerful and smoother operating, enhanced by excellent lubrication for an effortless ride. 5,Enhanced Integration: Meticulously machined on precise equipment, this freewheel offers clear threading, secure integration with the hub, creating a tighter and more seamless fit. Item Type: 3 Speed Freewheel Material: Steel Gear Ratio: 18 21 24T Size: Approx. 98x98x16mm or 3.86x3.86x0.63in Application: for Spin Hub, English Thread B1 3.75x24T 1 x 3 Speed Freewheel Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.