The Bre'el class was a type of Klingon starship in use in the 24th century. The IKS Kring was a Bre'el-class starship. (TNG - Slings and Arrows eBook: Enterprises of Great Pitch and Moment)

This reference may have been intended to be to the 23rd century B'rel-class, given the description of the Kring as an old, deteriorating ship.