Smith & Wesson Model 637, Performance Center, Double/Single Action, Metal Frame Revolver, J-Frame, 38 Special+P, 1.88 Barrel, Aluminum Alloy, Matte Finish, Silver, Wood Grips, Fixed Sights, 5 Rounds 170349 Performance Center guns originate from standard designs or are created from the ground up. From hand-cutting and fitting to fine tuning for precision, these firearms are top performers. Products from the Performance Center are the ultimate expression of old-world craftsmanship blended with modern technology. The Performance Center Model 637 features Enhanced Action, Aluminum Alloy frame and Custom Wood grip.