Polyvances Sensor Hole Cutter Set lets you cut perfectly round holes into new and aftermarket bumper covers. The newly-created, parking-distance sensor holes are cut cleanly with a perfectly finished edge. Quit using a stepped drill bit. Polyvances quality and well-thought-out design makes it way easier to use than a lot of the sensor hole cutter kits out there. Most other sensor hole cutter kits rely on some clunky dies and punches that must be flipped over in the correct order to cut the hole. The so-called "cutter" doesnt have a sharp edge to cut the plastic. Instead, the plastic is stretched until it breaks as it get jammed into the die leaving the bumper stretched, warped, and dimpled. Not only that, but cutting a hole requires four pieces... a bolt, a "cutter" (if you want to call it that), a die, and a nut. All of these pieces must be stacked in a convoluted way to even get started. (And, you ARE going to drop pieces trying to stack the pieces.) Plus, you are going to need two wrenches... one to drive the bolt and one to hold the nut. Polyvances sensor hole cutters have a sharp-edged cutter that slices through the plastic and wont stretch and warp the plastic. Because our dies are threaded already, you dont need two wrenches.