From The Manufacturer/Wikipedia/People Smarter Than Us:
This two shot double action derringer now comes in either .38 Special or .40 S&W. The barrel, receiver and internal parts are made form high strength stainless steel. Grips are available in a number of hardwoods. Our DA38 weighs just 14.5 oz and has dimensions of 4.84 x 3.3 inches, with a thickness of 1.1 inches and a 3.3 inch barrel. The DA38 has a hammerblock thumb safety and a Satin Stainless finish.