Pretty sure the 6400 and 6600 are the colander-equipped units shown in the "rediscover radio" ads. It has been a long development cycle, but the wearable Flex is now ready for delivery. The -M suffix reveals that optional Marinara Sauce is going to be an option. So, with the 6400/6600, we will be able to enjoy "signal straining" filter technology, wearable interfaces, and be able to (with the -M) season signals to taste. Reception will be enhanced through the use of a new ADC (al dente circuit) which promises superior dynamic range using just a wet noodle for an antenna.