From 1967 the tenor mouthpiece was offered in two types of tone chamber, the A (standard) and the B with more brightness/edge. The baritone and alto had the standard chamber design.

The B model proved to be more popular and so in the late 60s / early 70s Lawton standardised all three sizes (alto, tenor, baritone) on the popular design which became the new “Plain”.

In 1973 Lawton produced a design with more edge still and this became the “new” B model (tenor first and then alto and baritone a couple of months later), as Geoff said: “with what I consider to possess the maximum edge that I would wish to incorporate into my mouthpieces.”

In 1984 the design of the “Plain” models was changed by using “a slightly lower baffle” and “opening the throat a trifle to give a slightly fuller, darker sound”. This made for a greater difference in sound between the Plain and the B or BB models. The throat modification was also said to help intonation on the soprano.