To homologate the 1968 911 for competition purposes, Porsche began with the Spartan 911 T which were a full 54 kg (118 pounds) lighter than their 'S' siblings. Porsche offered clients the opportunity to buy a 911 T outfitted with competition equipment directly from the factory, and the resulting cars have become known as the 911 T/R. They were built in low quantities to a range of specifications depending on their intended competition purposes.