DC gear motor, specifically a N30 3.7V - 6V 150RPM model with a 30:1 metal gearbox. It is used to convert electrical energy into mechanical energy, typically in the form of rotational motion. 
Here's a breakdown of its features and applications:

• Function: Electric motors like this one convert electrical energy into mechanical energy. 

• Gearbox: The attached gearbox reduces the motor's speed while increasing its torque. This is important for applications requiring more power at lower speeds. 

• Applications: These motors are commonly used in robotics, RC cars, toys, and DIY projects. 

• Voltage: This motor operates within a voltage range of 3.7V to 6V. 

• RPM: It has a speed of 150 revolutions per minute (RPM).