Here's a great product if you've lowered your car and installed a turbo tie rod kit.
By changing the ride height you've now induced what they call bump steer. Because your tie rods are at an angle due to the lowered vehicle, you'll get and unexpected jerk in your steering wheel when you go over a bump. This is your solution. These are also required if you've raised the spindles on your struts.
What's cool about these? The joint is already sealed so you do not need an extra rubber boot. Again, because of the female mounting end, these only work with turbo tie rods.
Sold as set. 1 set required per car.