I had a few older 140MM STI Gen 2 magazines with worn out springs and unreliable lockback. I purchased Dawson precision baseplates for the 140MM tubes to replace the gen 2 plastic basepads. I then purchased these 11 coil +18% lockback follower kits. I generally use these magazines for training days and they now perform better than my current duty magazines. I ended up purchasing a 10 pack of +18% springs to be used in my many other 140mm Gen 3 Staccato magazines as needed. I'll continue to evaluate the followers + springs but can confidently recommend them to people.