JetLoader J-Frame – This precision spring loaded revolver speed loader is designed to load: S&W models 36, 36LS, 37, 38, 49, 60, 60LS, 442, 337, and Ruger SP 101 Series - .38 Special and .357 Magnum. Just a single straight push and the operating spring actually drives the cartridges into the cylinder. Lets you reload in any position even vertical. Twist lock loading holds ammo secure and rattle free.