They are also called spring knuckles ...
Make sure you located them where they won't rub against anything.
I install two on each side of the 300's rear springs after being sent the wrong replacement springs .....
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)