Features 1. Bicycle single disc gears are made of strong aluminum alloy, providing wear resistance, resistance to deformation, and high strength. The appropriate thickness ensures they will not bend. 2. The ergonomic round shape effectively uses precision punching to increase chain traction, reduce leg and knee strain, and ensure a smooth, stable ride. 3. The unique tooth profile design increases chain contact area, improves engagement, and reduces chain slack, allowing for reliable performance on rough terrain. 4. The narrow-wide tooth design securely holds the chain, helps protect the frame from scratches, extends component life, and reduces friction and noise. 5. Positive and negative chainring design eliminates the need for a front derailleur, reduces overall bike weight, prevents chain drop during riding, and minimizes maintenance issues. Item Type: Bicycle Positive and Negative Sprocket Material: Aluminum Alloy Size: Outer Diameter: Approx. 160mm / 6.3in Bolt Circle Diameter (Adjacent): Approx. 74mm / 2.9in Bolt Circle Diameter (Diagonal): Approx. 104mm / 4.1in Number of Teeth: 38T Compatibility: 38T Single Chainring, suitable for mountain bikes, cruisers with 32+ gearing or expansion cassettes, and performance riders. Package List: 1 x Positive and Negative Gear Disc