1,GOOD QUALITY METAL MATERIAL: Made of good quality metal material, the surface of the gear is rust proofed, which is durable 2,ACCURATE POLISHING: Gears are milled using pricing milling technology to ensure high accuracy, you can use with confidence 3,EXTENSIVE COMPATIBILITY: CJ0618 gear is compatible with micro lathes and metal cutting machines, very applicable 4,6 KINDS OF SPECIFICATIONS: there are 6 kinds of specifications for you to use, useful and practical to meet different using needs 5,GOOD WEAR AND HEAT RESISTANCE: HT250 gray iron material, possess good strength, wear resistance, heat resistance, good vibration damping, and excellent casting performance 2 x T60 Gear2 x T50 Gear2 x T40 Gear1 x T45 Gear1 x T35 Gear1 x T30 Gear Item Type: Metal Gear SetMaterial: HT250 gray ironSpecification: Model Diameter(approx.) Thickness(approx.) Teeth T60 62mm or 2.44in 7mm or 0.28in 60 T50 52mm or 2.05in 7mm or 0.28in 50 T45 48mm or 1.89in 7mm or 0.28in 45 T40 42mm or 1.65in 7mm or 0.28in 40 T35 37mm or 1.46in 7mm or 0.28in 35 T30 32mm or 1.26in 7mm or 0.28in 30 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.