The RugerA(R) Mark(TM) series .22 pistols have renowned popularity, until cleaning time. We have all heard and read the stories about how frustrating disassembling and reassembling can be. Too many of us have just avoided it. No more! Now, with the user friendly, All-In-One Tool, there is a simpler, safer, and faster, method to clean our guns. The tool works on all the Mark series I, II, III(TM), and 22/45(TM) pistols with a square recess in the mainspring housing. and without altering the gun. For new guns or excessively dirty guns, we recommend the accessory stand. The stand frees up your second hand, allowing for more pressure to be placed on the durable tool which even Mfg: The Right Tool Co.