Smith & Wesson 163690: Smith & Wesson J-Frame revolver is designed to fire a full power round and is as simple and easy to use as it is reliable.The Model 640, is a variation of the Model 40 Centennial which integrates the time-tested features of the original with modern advancements. It is a small-frame, concealed-hammer revolver that packs a full-sized punch.This model has a stainless steel frame barrel and cylinder, blade front and fixed rear sights, and black synthetic grip.,Smith & Wesson J-Frame revolver is designed to fire a full power round and is as simple and easy to use as it is reliable.The Model 640, is a variation of the Model 40 Centennial which integrates the time-tested features of the original with modern advancements. It is a small-frame, concealed-hammer revolver that packs a full-sized punch.This model has a stainless steel frame barrel and cylinder, blade front and fixed rear sights, and black synthetic grip.