I live in a 50 year old home that, for it's time, was quite innovative and well- equipped considering it included an insinkerator disposal. The disposal used a "key" turn in-sink mechanism to operate the device as opposed to flipping an on-off wall switch or depressing a button mounted somewhere on the sink. Though only the second owner of the home, I believe this was the original disposal put in when the house was built. Only recently did I replace the disposal because I could not find a plumber who could fix the key operation (one of the nubs that the "key" latched on to wore out). No question, i replaced the original with the same type insinkerator -except this time it is a model even safer, easier to use, much quieter and oh so efficient. Thank you