Basically it's a tear off that the first layer sticks to the shield with a temporary adhesive, and the other layers are pre-laminated to the top of it. This gives you up to seven layers of optical grade Mylar that you can wipe with your glove during a race, without scratching your shield. When a layer gets scratched like your shield would have, you just pull a layer off and start over. Another benefit is if you were running a race that went day into night, you could start with smoke or amber, and then when it gets dark you can pull the whole thing off to get to your unscratched clear shield. These are a little more difficult to pull than a standard tear-off because of the small pull tabs, so you will probably be removing them when stopped between sessions or in the pits. If you require tear-offs, they can be used over the Shield Saver to extend the life of a shield. Each package contains 3 clear laminated 4mil thick layers, or 7 laminated layers of amber or smoke tinted 2 mil thick layers.