Our shop is based on the principle of "service and quality first" and we look forward to welcoming every customer.10T 1mm Metal Copper Gears for Model Cycloidal GearSmall module gear is used for toy accessories, for mini cars, for remote control aircraft etc.How to calculate the calculation of gear? (for reference only)Gear module M = outer diameter ÷(number of teeth +2)Outside diameter = Gear module ×(number of teeth +2)Thank you for your visit, any problems can be contacted and resolved in person with the shop!