From Floating Forest Pedals:

The Drifter is a somewhat wild delay pedal. Its more tamed characteristics include your standard Rate control and a Mix control as well. The middle stomp switch is a temporary Swell which raises your volume substantially over time as long as your Mix control is at roughly 70% or greater.

Its more unique features include a light sensitive rate control that moves away from your traditional potentiometer controlled rate and leaves your signal at the mercy of the light being feed to its LDR on the face of the Drifter. This is triggered by activated the stomp switch on the right most side of the Drifter. To add some control to this system the USB mount on the right side gives you an option to put most* USB powered LED lamps into it and add some light to the LDR. This USB is also connected to a flasher circuit which is controlled by the knob parallel to the USB.

Every drifter comes with a compatable USB light!