IKS P'Rang

From Memory Alpha, the free Star Trek reference.

The IKS P'Rang was a Klingon cruiser in service during the 24th century. In 2365, the P'Rang was ordered to rendezvous with the sleeper ship IKS T'Ong, returning from a 75-year extended mission. However, the P'Rang could not reach the T'Ong before its Federation-Klingon War-era crew revived inside Federation space, though the USS Enterprise-D was able to prevent the T'Ong from causing any damage. The P'Rang later escorted the T'Ong back to Klingon space. (TNG: "The Emissary")

The P'Rang was not shown on screen, so its specific class is unknown. In the episode, it was referred to, simply, as a "cruiser".