MECCANIXITY 92AA

What is this? Copper Gears suit for a science DIY project such as rc model electric robot and windmill, education such as displaying how gear ratios work, and any other family small motor DIY project. What will I get? Model gear,Outside diameter:5mm/0.2 Inch;Shaft diameter:1.95mm/0.08 Inch;Thickness:5mm/0.2 Inch;Type:92A:Module:0.5;Teeth:8 Teeth ;Material:Copper;Color:Gold;In the Package of: 10 x Copper Gears; Are there any advantages of the product? Copper gears are made of Copper material, it is durable, smooth, sturdy, and has a long service life. How to use it? It is easy and convenient to install and remove. What should I notice? Please check the size carefully before ordering.