I acquired my Mammut Smart from Mountain Gear in2009.
This Mammut Smart is 123 mm. tall, 58 mm. wide, 22 mm. thick, and weighs 81 g. It consists of two cylindrical pins and a plastic handgrip riveted between two side plates.
One side of my Smart is screened with "MAMMUT," the Mammut logo, and "0108." The other side is screened with "MAMMUT," a rigging illustration a book-wit-an-"i" icon, "ø8.9-10.5mm," and "Made in Italy."
The Mammut Smart is similar to the Camp Yo-yo, Salewa Antz and Wild Country Single Rope Controller. A bight is inserted into the left side (as shown) of the controller, and an HMS carabiner is clipped through the slots and the bight. The HMS is anchored appropriately. Rope is fed by turning the Smart horizontally (clockwise). During a fall, the Smart rotates toward the orientation shown, and the rope is wedged between the HMS carabiner and the lower pin. The belayer can fed rope by lifting the red arm. This upward motion is different than the downward one used with the Camp Yo-yo and Wild Country Single Rope Controller, but they both work. The long handle on the Smart helps make the lifting motion easier.