The Model 42 Centennial Airweight was the aluminum alloy version of the Model 40 Centennial, applying the Airweight concept to the hammerless DAO platform. It was the lightest and most concealable revolver in the S&W lineup for decades. Type: Revolver Action: DAO Caliber: .38 Spl Capacity: 5 Year introduced: 1952, USA Weight: 15 oz Overall length: 6.5" Status: Discontinued Intended use: Carry, Backup