Features 1、Cast steel material, provide greater overall strength, durable wear resistant. 2、MOD 0.8 gear, while aesthetically unique compared to the larger gears, will operate the same. 3、The combo will create a 7:1 ratio, underdrive or overdrive depending on whether you're set out to increase speed or maximize torsion. 4、A true maker is about integrating and repurposing, suitable for industrial robot. 5、15-teeth gear, with 6mm round hole, high-hardness, long service life. Specification Item Type: Gear Material: Cast Steel Product Model: S4304-0006-0015 Product Specifications: 6mm / 0.24in round hole 0.8 modulus Outer Diameter: Approx. 13.6mm / 0.54in Pitch Diameter: Approx. 12mm / 0.47in Package List 1 x Gear