The Master Switch is a great by-pass tool For Master padlocks #1,#2,#3,#4. By inserting both switch's deep into the keyway of the lock you are able to open the padlock. With the assistance of some padlock shims you can even open Master padlocks #5,#6.
The Master Switch is just a fun tool to use. You might be just as fast to pick the lock open but their is something to exposing a built in weakness and using a bypass tool.