I bought these to use with my FD-75PR and the product I received will not fit with my dehydrator. These replacement trays are not the same exact size despite they claim on the side of the box that they came in. They nest just fine on top of the older trays but the dehydrator top will not sit flush on these trays. The problem lies with the center air passage which is about a 1/2" taller than my original trays. They will nest with each other and presumably other models but not with the FD-75PR. I was skeptical that maybe my dehydrator was not the model I thought it was so I double checked the inside. I'm guessing they changed the product design sizes over the years and one of the things I have either the unit or replacement trays predates the other. I will return these and look for another fit.