This modules uses the PCA9685 PWM chip to control up to 16 servos at once using the i2c protocol. Apart from using only 2 i2c pins on an arduino this module sends the servos constant pulses using a built-in clock. This eliminates the timing problems commonly associated with the native servo library. 

Characteristics:

• 62mm x 26mm
• i2c address selectable by shorting out jumpers (default address: 0x40)
• Built-in 1000uF capacitor on the power line

Installing the Library

Connecting the module to an Arduino