Tip: If you wish a massive amount, please contact us, we will wholesale. we can additionally customize it. Parameter: Inner hole: many optional Material: Brass Practical handheld remote control aircraft, RC Car model, Gear Box and many others Option: Gear Number: Modulus: Outer Diameter: Thickness: Hole: Model 1 8T 0.5 5mm 5mm 1.98mm(fit 2mm shaft tightly) Model 2 9T 0.5 5.5mm 5mm 1.98mm(fit 2mm shaft tightly) Model 3 10T 0.5 6mm 5mm 1.98mm(fit 2mm shaft tightly) Model 4 12T 0.5 7mm 5mm 1.98mm(fit 2mm shaft tightly) Model 5 12T 0.5 7mm 5mm 2.28mm(fit 2.3mm shaft tightly) Model 6 14T 0.5 8mm 5mm 3.14mm(fit 3.17mm shaft tightly) Package Included: Gear * 1pc