Goof Ring by Kichler in White Material (Not Painted) from the Direct To Ceiling Unv Accessor collection.

The DtC Universal goof ring is intended for use with Direct-to-Ceiling (DtC) Slim, Recessed and Gimbal 4 inch Round Downlight fixtures. This white aluminum ring is designed to help cover an installation hole that may be larger than the intended DtC fixture. Utilize the ring between the ceiling and the fixture to cover the hole and proceed with Spring Clip installation.