Patroller Libra is the second unit of the 1^st series "Cassiopea" or "Costellazioni" class; was launched on July 27, 1988 at the Muggiano Shipyards, La Spezia, and delivered to the Italian Navy on November 28, 1989. On October 20, 1991, was given the Combat Flag of the National Association Italian Seafarers in Vasto.

These four sister ships (Cassiopea, Libra, Spica and Vega) have been specifically designed for maritime pollution clearance.

In the history of the Italian Navy, another ship had the same name Libra: a 1937 Spica Class Destroyer active until 1963.

Her international name is "I A T B". Her motto Patiens Vigil Audax (Patient, Vigilant, Daring) refers to the "virtues" of her crew members.

The Crest is circular, it depicts Lady Justice standing on a floating sea-shell holding balanced scales. Over her left arm are three stars: Alpha Librae, Beta Librae, Delta Librae, which form the most important group of the constellation Libra. In the upper part of the crest is the towered crown with rostra that reminds of the honour and valour of Roman seafarers, conquerors of lands across the oceans. In the lower part is the burgee with the motto of the Unit.

​ITS Libra is based at Messina, forms part of the First Patrollers Flotilla (COMSQUAPAT UNO), refers to the Patrol Forces for Surveillance and Coastal Defense (COMFORPAT), under the Command in Chief of the Naval Fleet (CINCNAV).

Main duties of the unit are: patrol of national coasts, fisheries patrol, migration flows control, Search & Rescue, anti-pollution activities, fight to illegal activities and international terrorism. Primary mission is Fisheries Patrol by means of Operation "Constant Vigilance," to safeguard national economic interests and control over the respect of international fishing regulations mainly in the Sicily Straits.

In March 2011 was the first Italian ship to provide humanitarian assistance to Benghazi and Darnah, during the Libyan crisis.

In 2013/2014 was engaged in Operation Mare Nostrum with the 29^th Naval Group Command.