ITEM NAME:Folding Bike Chainring BCD 130mm Chain Ring Narrow Wide Chainwheels 52T Description: Premium AL6061 aluminum alloy CNC machined process folding bike chainring- corrosion resistance, ultra-light but high strength Standard 130mm BCD; for 9~11 Speed; 50-58 Teeth Designed to reduce friction and noise and ultra-light won't add any burden to your bike Longer and narrow wide teeth increase the grasp force and make you no longer worried about the chain dropped Thickened (4mm) makes it stronger and more durable Specification: Color: Black BCD: 130mm Thickness: 4mm Teeth Length: 7.2mm 50T Outter Diameter: 20.8cm / 8.2 inch 52T Outter Diameter: 21.6cm/ 8.6 inch 54T Outter Diameter: 21.6cm / 8.6 inch 56T Outter Diameter: 23.1cm / 9.1 inch Package Includes: 1 Piece Folding Bike Chainring (without bolts) SKU: ALU0015330966022708.Standard 130mm BCD; for 9~11 Speed; 50-58 Teeth. BCD: 130mm. Premium AL6061 aluminum alloy CNC machined process folding bike chainring- corrosion resistance, ultra-light but high strength. 1 Piece Folding Bike Chainring (without bolts).