What was the name of the 1926 agreement that stabilized relations between studios and unions? film?

It was called the Basic Studio Agreement and it was signed on November 29th, 1926.

More than just a contract, the Basic Studio Agreement was the first agreement to be signed between the powerful Hollywood studios and film industry worker unions. In it, both film producers and the unions stipulated the first true agreement that would regulate negotiations related to wages, hours, grievances and general working conditions.