The Smith & Wesson Airweight is a variation of the J-frame 5-shot revolver. The Airweight is made entirely of aluminum alloy and was first introduced in 1951.
The Airweight was originally introduced as the Model 37, but the aluminum cylinder was unable to stand up to the pressure of a .38 special round, so the gun was quickly discontinued. The current Model 442 and Model 642 use a steel cylinder with an aluminum alloy frame, allowing them to handle the punch of .38 special round, as of 2015.
Both the Model 442 and Model 642 are identical, except the Model 442 is all black while the Model 642 comes in a silver matte finish. Both guns are compatible with Crimson Trace laser grips, but they come standard with Boot Grips from Uncle Mike's made of black elastomeric material, perfect for absorbing recoil. Both guns also have enclosed hammers, while other J-frame variations have exposed hammers.
The Airweight is designed to be compact and easy to conceal and carry. Both guns only weigh 15 ounces when unloaded and are small enough that they can fit in a purse or bag, but they are also holsterable, both in a belt holster and a pocket holster.