Perfect replacement for covering mounting holes on the bottom of sliding patio doors. I would say they are about 1/32 inch larger than 2.5 inch. This way they fit snugly and don't come out of the 2.5 inch holes.
Pros
Head diameter: 16.6 mm / 0.65". Bottom Diameter: 12.7mm/0.50inch Mounting hole diameter: 13mm/0.51in