Boot and bumpstops are a small, but important part of a strut suspension.
The boots help cover and protect the chrome shaft of the strut from dirt
and debris. The Bumpstop part protects the car from bottoming
out or causing damage when the suspension goes beyond it's normal
travel. The image above shows an example of two kinds. They vary in looks,
depending on the vehicle. Some vehicles do not have them at all.
But in most cases, if yours are in good shape, you do not need
to replace them. But in the long run, you remove them anyway
when changing a strut, so it can be cost effective to change
them while the strut is off the car, rather than having to take
the car apart later again to replace them. Note that failing
to replace a missing or defective Boot/Bumpstop can cause pre-mature
failure or damage to a unit.
Boot/Bumpstops are made by several companies, depending
on the application and availblility.