This is a 5V Arduino running the 16MHz bootloader.  Arduino Pro Mini does not come with connectors populated so that you can solder in any connector or wire with any orientation you need.  The Arduino Pro series is meant for users that understand the limitations of system voltage (5V), lack of connectors, and USB off board.

 

This board connects directly to the FTDI Basic Breakout board and supports auto-reset.  The Arduino Pro Mini also works with the FTDI cable but the FTDI cable does not bring out the DTR pin so the auto-reset feature will not work.

 

Features:

•     ATmega328 running at 16MHz with external resonator (0.5% tolerance)
•     USB connection off board
•     Supports auto-reset
•     5V regulator
•     Max 150mA output
•     Over current protected
•     Weighs less than 2 grams!
•     Reverse polarity protected
•     DC input 5V up to 12V
•     On board Power and Status LEDs
•     Analog Pins: 8
•     Digital I/Os: 14
•     18mm x 33mm / 0.7" x 1.3"