Features :

L293D is a monolithic integrated, high voltage, high current, 4-channel driver. Basically this means using this chip you can use DC motors and power supplies of up to 36 Volts, that's some pretty big motors and the chip can supply a maximum current of 600mA per channel, the L293D chip is also what's known as a type of H-Bridge. The H-Bridge is typically an electrical circuit that enables a voltage to be applied across a load in either direction to an output, e.g. motor.

Specification:
2 interface for 5V Servo connected to the  high-resolution dedicated timer - no jitter!
Can drive 4 DC motors or 2 stepper motors or 2 Servo
Up to 4 bi-directional DC motors with individual 8-bit speed selection
Up to 2 stepper motors (unipolar or bipolar) with single coil, double coil or interleaved stepping.
4 H-Bridges: per bridge provides 0.6A (1.2A peak current) with thermal protection, can run motors on 4.5V to 36V DC
Pull down resistors keep motors disabled during power-up
reset button
2 external terminal power interface, for separate logic/motor supplies
Tested compatible for  Mega, Diecimila & Duemilanove

Package Contains:
1Nos L293D motor Driver shield