The Dynamat Xtreme sound-deadening sheets are available in a variety of sizes for different applications and can be cut for a precise fit. Here you can see the peel-off backing and the self-adhesive underside. That adhesive is sticky stuff so position the pieces carefully when installing them. You might find it easier to remove the backing a few inches at a time instead of all at once. If cutting is necessary, it should be done before the backing is removed.