This is one of those "common sense" products that people forget common sense when using. The ideal use is when installing speakers in your doors or deck. More powerful speakers bring out every vibration in your vehicle and can sound tinny. Applying a sound deadening material when installing speakers is pretty much a requirement. This box has enough for two larger oval, or three smaller round speakers. It will help reduce vibration and slightly "flatten" the sound. If you have a noisy trunk - especially in the wheel wells, this will also help deaden the sound - but you'll probably need two boxes.This is a SMALL quantity of material. 1.76 x 1.76 feet. Cut a piece of paper that size - it's not that much.  If you need to deaden sound in a small problem area, it will work.  Consider it a "small project" size.  Anyone expecting to make a $15,000 car sound like a $60,000 car by adding sound deadening is dreaming.  You'd have to strip the car of almost all the interior, door panels, dash, etc. to apply the stuff - hardly a practical solution, or anything 99.999% of the population could do!Application: The instructions show using scissors - I prefer a utility knife with a piece of scrap wood as a cutting surface. This stuff looks and feels like a mixture of tar and rubber, and leaves a gummy residue on the scissors. You can clean this off with solvent, or as most guys do, with gas (I don't smoke.)  I'd rather just throw away a 10 cent blade.1) For oddball shapes or curved areas, make a paper template and cut that to shape. Put that on top of the mat as a template and cut.2) Clean the application area with rubbing alcohol and let dry3) Use a blow dryer on the mat to soften it up - this is by feel, but you want to flexible.4) peel and apply.Scrap pieces can be used to fill in small areas or cover seams, holes, etc.If you have a rust-bucket (I've had a few) and have water coming in the floor boards or trunk, this stuff is a nice patch material.  If you can find the hole, say in the floorboard, sand the metal to remove the rust and paint - ideally inside and out. Apply a piece of this inside, overlapping the hole by about 1" on all sides. If you can, do the same thing on the outside. Where the patches meet they will bind together. This forms a seal/plug and keeps the water out. You'll need to cover the patch in something - carpeting, etc. in areas where you'll step on them.(floorboards, for example.) If you have a swiss-cheese rusty piece of metal, clean as best you can - you need clean, bare metal - not rust - in order for this to stick. Heat the metal (if it can be done safely, use a torch) then apply the mat. It will melt into the holes!  Otherwise, heat the metal with a blow dryer, apply the mat, then heat up as hot as possible with the same blow dryer. Apply pressure. The idea is to press the now soft mat into the holes.  Instant large area patch!