Genuine OEM replacement part, this item is sold individually.
As the description says, this is the Steering Shaft for all of the Lawn Tractors shown below.
One of the most popular reasons this part is replaced, is that the gear on the shaft becomes worn or stripped.
It is advised that you check the part number 717-0622C Steering Gear Segment, before replacing the just the Steering Shaft.

Genuine Manufacturer Approved Carriage Bolt is a standard part that fits a variety of products. This part is sold individually and the Nut is not included. The square area under the head is designed to fit into a square hole in the work piece it measures 5/16-18 x .75. It is this square hole that restrains the bolt and keeps it from turning when the nut is tightened.

This is a genuine manufacturer-sourced replacement hardware that is commonly utilized on Craftsman lawn and garden equipment. A lock nut is a type of nut that resists loosening when it is properly threaded onto a bolt. This is a standard hardware which has multiple applications depending on your unit, make sure to check appropriate diagrams for correct location and use of this item. Please note this durable metal lock nut is sold individually.

This is an authentic replacement part manufactured for use with Craftsman walk-behind lawnmowers. The blade is angled to allow the clippings to rotate through the cutting deck to produce fine clippings for side discharge and mulching. Lawnmower blades wear out over time and can cause the grass blades to tear making frayed endings that can diminish the look of the lawn. A new mower blade will allow for a cleaner cut keeping the lawn looking good. This blade is sold as an individual replacement part.

This is an authentic manufacturer sourced replacement cotter pin. It is a standard hardware commonly used on a variety of Craftsman lawn and garden equipment. Depending on the model of your equipment it will be used in different locations to secure two parts together. Please make sure to check appropriate diagrams for correct application for this part. This metal cotter pin is sold individually. It is best to use pliers to remove or install this part.

This is an original part from Craftsman for use with Lawn Mowers. The mulching plug, when installed in the grass-discharge chute, converts the mower to mulching mode. The most common reason for replacing the mulch cover is if it is damaged. This part is sold individually. The tool that you will need to replace the mulching plug is a 3/8” nut driver.