VW Transporter T5, T5.1, T6 & T6.1 (2003 ~ current year). These dust covers clip into the top mount bearing, ensuring dust and dirt does not enter your front shock absorber. Not using dust covers on OEM Struts or Coil-overs can cause dirt to protrude the O’Rings (oil seals) which may cause your struts to leak causing and knocking.