all new rubber parts and hardware to boot. beats spending 100 on a whole new assembly. make sure to lap the metal mating surfaces on a flat surface with some sandpaper before reassembly, mine were pretty warped. be careful squeezing the new diaphragm through the plastic part. i put some thread tape on the mounting bolts just in case the supplied washers didnt totally seal. maybe couldve gone without every bolt and piece being individually packaged just to save some waste. i like rebuilding stuff rather than tossing it.