From The Manufacturer/Wikipedia/People Smarter Than Us:
The Ruger® Redhawk® revolver was Ruger's first double-action revolver specifically designed for the powerful 44 Magnum cartridge. It embodies many advanced features such as a “triple-locking” cylinder, a unique “single spring” mechanism for relatively lighter trigger pull, replaceable front sights and adjustable rear sights, with an all-stainless steel construction.