Three signal inputs are provided for dimming control. You can use the PWM signal from an Arduino or your favorite microcontroller to dim each channel individually, or you can tie them all to the same PWM for simultaneous dimming. Dimming can be done by an analog voltage (20%-100% of max current by varying voltage from .5V-2.5V) or by PWM (so long as PWM minimum voltage is less than .4V and maximum voltage is more than 2.4V) for a full 0-100% range. A small jumper is provided for each channel to allow you to increase the drive strength from 330mA to 660mA. Two mounting holes for 4-40 or M3 screws are provided on either side of the board. They are perforated so they can be easily snapped off with a pair of pliers, if a smaller footprint is desired. Download documentation here: http://www.electronics123.net/amazon/datasheet/PicoBuckV12Schematic.pdf http://www.electronics123.net/amazon/datasheet/picoBuck_v12.zip http://www.electronics123.net/amazon/datasheet/AL8805.pdf https://learn.sparkfun.com/tutorials/picobuck-hookup-guide-v12 http://protofusion.org/wordpress/2013/03/picobuck-rgb-led-driver/ https://github.com/sparkfun/PicoBuck