Here is an original condition Meyer Bros "Tru-Flex" 4M alto piece This piece measures .070" on my gauge.
Frank and Ed Meyer, better known as the Meyer Bros. were once shop employees of Otto Link as finishers who eventually started their own business. Before they promoted their 'lapped facings' they experimented with something they called the "Tru Flex" with a cutout in the table. Early manufacturers would often put something known as a 'French curve' on their mouthpieces which included a concavity in the table. The Tru Flex was likely an idea based on this concept.
This piece is an excellent example of the American style of mouthpiece making and finishing, something I look to as an example of hand finished quality. While not as punchy as later examples it really is a piece of art that can be used to play music with!