Aircraft instrument hole reducer adapter

In general aviation aircraft, the round instruments mounted in cockpit panels are generally one of two common sizes: 2-1/4" (57mm) and 3-1/8" (80mm). MS33638

This thing is an adapter plate that allows you to utilize a 2-1/4" instrument in an aircraft panel hole that was designed to fit a 3-1/8" instrument.

The design is made so that the surface of the adapter should be able to sit flush with the surrounding panel, however the actual 2-1/4" instrument will be slightly recessed behind the in