I recently purchased a used but like new teknetics delta 4000. It seems to function fine, however, the online owners manual for the delta 4000 shows that its supposed to have an A1 and A2 mode in the all metal setting. I can find no A1 or A2 modes on this delta. This machine is an early model that i believe was manufactured around 2009. Does anyone know if these early delta 4000 detectors came without this feature? If my machine has an A1 and A2 mode - i can find no way to access it. It's no big deal either way...just wondering why this machine does not have this