American Defense mounts have two different types of springs, Generation 1 and Generation 2. The Gen 1 springs are the old style springs that are the same diameter throughout the spring. They are silver in color. The Gen 2 springs have one larger end, that is captured in the spring pocket on the mount to prevent it from falling out. They are gold in color. When you request replacement springs, please specify which generation springs you need. Generation 1 mounts are being phased out and all newly manufactured ADM mounts will be Generation 2, although there are still some Gen 1 mounts in circulation with our dealers and distributors.