The Argentine Submarine Force (Spanish: Comando de la Fuerza de Submarinos, COFS) is the submarine service branch of the Argentine Navy. Argentine submarines have traditionally been named after the provinces of the Republic whose name begins with the letter 'S'; they are home based at Mar del Plata naval base. COFS members have the same rank insignia and titles as the rest of the Navy. As of 2010, the elite group Agrupación de Buzos Tácticos is under the direct command of the submarine force; two TR-1700 and one Type 209 submarines are in service. Two small surface vessels, ARA Punta Mogotes (P-65) and ARA Luisito (Q-51), are also part of the COFS and used in the training role.