The Hammer Cage is used to relieve all spring tension on the AR-15, M-16 and AR-10 hammer when installing or removing the hammer and hammer pin. Simply slide the Hammer Cage over the hammer with a hook leg on each side and to the rear of the receiver. Pull back on the hammer and cage and use the included spring tool to lift the legs of each side of the spring onto the leg hooks of the Hammer Cage. Spring tension is now removed and the hammer pin can now be used using the opposite end of the spring tool. The hammer along with the cage can now be removed from the receiver as one piece. To reinstall the hammer, simply follow these instructions in reverse.