Opens with your vehicles ignition key eliminating extra keys on your ring; Works with center cut Chevy, GMC, Buick & Cadillac keys Fits couplers From 1/2" to 3-3/8" wide Lock slides along stainless steel pin for ease of use, 1/8" incremental adjustments ensure a snug fit Stainless steel lock shutter to keep out dirt and moisture, plate tumbler sidebar to prevent picking and bumping Limited Lifetime Warranty