KEF's first products formed the three-way K1 Series but with the 1962 introduction of the now world famous B139 bass driver, the best-selling Celeste was born and gave the company the much needed early success and stability from which it could grow and prosper. The B110 and T27 drivers followed in 1967 and were successfully utilised in the Cresta and Concerto and later selected by the BBC for use in the LS3/5A monitor. The manufacture of monitor loudspeakers such as the LS5/1A for the BBC provided KEF with useful experience in working to tight acoustic tolerances. By the end of the decade KEF was established as a leading company in the audio industry with commercial and critical success not only for the KEF loudspeaker systems but for the drive units which were adopted by numerous companies around the world into their own systems.