MECCANIXITY 30122BA - 30Pcs 30 Teeth Plastic Gears

What is this? Plastic 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:16mm/0.63 Inch;Shaft diameter:2mm/0.08 Inch;Thickness:5.4mm/0.21 Inch;Type:30122B:Module:0.5;Teeth:30 Teeth ;Material:Plastic;Color:White;In the Package of: 30 x Plastic Gears; Are there any advantages of the product? Plastic gears are made of plastic 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.