Designed to replace the standard MIM cylinder stop, this upgraded Steel cylinder stop offers exceptional cylinder lock-up and is guaranteed to last far longer than the stock cylinder stops. MIM cylinder stops break, it’s not if, it’s when. You'll be surprised how much difference a new part can make especially when it comes to reliability. Specifications:  Heat-treated 50 Rockwell Hardness  Fits K-L-N frame models Made in America Premium Grade Stainless Steel.    Key Benefits Major Boost in Performance. Our parts are geared to boost S&W revolvers to bring you accuracy, comfort, and reliable maintenance to all of your revolvers, guns, pistols, and other firearms.  Quality Testing. Each of our items is successfully tested and certified to give you reliable results and power. With the best price available on the market, you'll get the best value.  Reliable Materials. Our materials are sourced from renowned producers in the market. It is our pleasure and pride to give you the best items made from the best alloys available. 100% Replacement Guarantee! We provide a 100% replacement guarantee so you do not have to worry about broken parts once they have arrived at your doorstep. Send a picture as proof of your concerns and we will respond as soon as possible.