The Blind Mark: Arc Mark - The Five Easy Steps

Step 1 Screw Center Mark Target into the light bulb socket inside the recessed light fixture, Let the telescoping magnet extend down pass the ceiling level.
Step 2 Once the Center Mark Target is installed in the recessed light fixture, cover the recessed light fixture with the drywall. Position your drywall in the exact location and fasten it with enough drywall screws to make it secure.
Step 3 With the magnet face on the Center Mark Locator facing up, pass the Locator across the area in which the Target is located. Find the Target and let the Locator snap in place.
Step 4 1)With your spiral saw plunge the tip of the bit cutter into the drywall on the outside of the Locator and move to the out until you make contact with the inside wall of the recessed light fixture . 2) Pull the cutter out of the drywall and jumping the wall of the recessed light fixture, about ¼ inch I bit more then the thickness of the light fixture, and plunge the tip of the bit cutter into the drywall on the out side of light fixture. 3) Move the tool slowly towards the center and counter clockwise 360 degrees around the recess light fixture.
Step 5 Remove the drywall cut out and the Center Mark Target. Finish screwing the drywall.And you’re Done!!!