These DVD's were edited from gunsmith training course materials and were originally available only as companion videos for the Kuhnhausen Colt .45 Auto, S&W Revolver, and Volume I Colt D.A. Revolver Shop Manuals.Although these DVD's are still suggested for that purpose, because they add extra chapters to their corresponding manuals, all three programs stand by themselves and provide additional practical gunsmithing information.FeaturesGunsmithing the S&W J, K, L, & N Frame Revolvers (non powdered metal part revolvers manufactured through mid 1999)