Oh okay I used to think piezos were alot newer. Never realized they went as far back as 1980 ( I was 7 at the time ). I only ever heard units back then that had squealer horns. Wow that is amazing how the stains came off the cover of that other Sears unit. That is probably what the unit looked like when it was brand new nearly 40 years ago. After it being up on the ceiling for 35 plus years it sure puts up with alot.