The Shirekral class are Romulan vessels that were common during the Earth-Romulan War of the 22nd century. Examples of the Shirekral class remained in service into the late 23rd century, but those later ships had the original ion drive replaced with the singularity drive used by the Romulans into the 24th century.
The role served by the Shirekral class (warship, transport, patrol craft, etc.) is not specified. (ST novel: Articles of the Federation)