When you need to core an apple this is a very handy gadget to use. It has a serrated edge and it goes right through the whole apple; then just pull it out and you have successfully cored an apple. I like to make dried apples as snacks, with a little cinnamon/sugar mix and this gadget makes this process very quick and easy. By the way this makes a good Weight Watchers snack.
Recently (9-20-13) I made an apple recipe where I did not peel the apples. Using this gadget was quick, easy and cored the apples perfectly. I have a Rosle apple corer but there are many brands available. Recently I saw one that actually ejects the core so you do not have to dig it out.