KYB Shocks & Struts Strut Boots Rear Chevy Cruze 16-19 / Volt 16-19 | SB145

This is a boot / bumpstop.

You only need to order these if the boot / bumpstops on your car are missing or worn out.

Normaly, your original boot / bumpstops are simply reused. But you do have to remove them while changing out a unit, so while you are there already doing the work, it's easy to just slip the new parts on since you already have the car apart.

The illustration shows 2 kinds, the one to the left is an older style, the one on the right (eventually) will replace the left ones as the manufacturers continue to improve their products over time.

Both are the correct part, and both are designed to fit your vehicle. (they may look slightly different, but they are the same part and do the same thing).