Close unneeded panel holes and electrical knockouts. Quick and easy installation. Convex, matte finish head tapers to thin edge (Except DP-187). Multiple sizes for use in .187" (4,7 mm) to 6.000" (152,4 mm) diameter holes. Lock firmly into panel up to .250" (6,4 mm) thick. Locking fingers in fractional increments up to the maximum panel thickness. Approximate Head Thickness: .062" (1,6 mm). Thickness may vary. For Snap-In Metric Dome Plugs, click here.