My 1987 Model 333 InSinkErator failed ;last week after 30 years of faithful service. I bought a new model 46 and I was able to remove the old model without difficulty and install the new one. Absolutely no problem and after about 2 hours work I have a new waste disposer up and running.. I cannot recommend this product highly enough. If you are concerned about fitting it don't be, it is straightforward and the instructions supplied by the manufacturer are very explicit.