OK....These camera / dolly track wedges are cool. First off, they're serrated so they won't slip. Next, they have been tested to support over 10 tons, yet they weigh only a few ounces. Lifetime guarantee. Actual dimensions 3.5" x 6" x 1". Made from Recycled Material (ABS plastic). Filmtools offers a lifetime warranty on this product. If it breaks we'll replace it for free.