# Structure

## Metal Material

While being a seemingly insignificant factor, choice in metal material can have a drastic impact on a robot's performance. There are two types of metal used in VEX products:

### Characteristics

<table data-header-hidden><thead><tr><th width="361.5">Steel</th><th>Aluminum</th></tr></thead><tbody><tr><td>Heavier Material</td><td>Lighter Material</td></tr><tr><td>More Rigid and Durable</td><td>Easier to Bend and Break</td></tr><tr><td>Appears Darker and more Reflective</td><td>Appears Lighter and flat</td></tr></tbody></table>

### On the Robot

Due to its lighter weight, aluminum should be used in subsystems that need to be kept as light as possible, such as lifts and game piece manipulators.&#x20;

Steel is commonly used in areas where weight is less of a concern, or when a subsystem needs to be made heavier. In the event of a drive ratio favoring torque, a robot can be made heavier to help prevent being pushed by other robots.

As a general rule, however, aluminum should be used in the vast majority of places. Having a heavier robot, unless designed to be so, can be detrimental, and using aluminum instead of steel helps to drastically reduce the weight of a robot or subsystem.