There cannot be any particular effect described here. It has unlimited use. Use it to vanish, appear or change one item for another. You can show the bag empty by opening the zipper at the bottom of the bag and passing your hand right through. The audience can see through and through and believe that there cannot be anything concealed in it. However, unknown to the audience, you can conceal in it articles like silk hanky, an egg, etc. You can also bring the bag empty, then put inside a hanky, etc., and make it disappear. Again open the zipper to show through and through.