This is an OEM replacement part sourced directly from the manufacturer. Sold individually. This no grease mandrel assembly includes housing, shaft assembly, bearing, and nut only - pulley/washer and blade bolt/washers are not included.
This is the part the mower blade attaches to, it is mounted to the deck of the mower by four bolts.
Spacer must be installed under the pulley.
Installing with the spacer on top of the pulley (or failing to use spacer) will result in damage to shaft and pulley.
The mounting holes on the Mandrel are not threaded. But the bolts that are used to secure the mandrel to the deck are self tapping. The Mandrel shaft goes thru the deck and the pulleys are attached to them, then the belt that drives the mandrels is placed in the pulleys.