Replacement center  cap o-ring kits. Oil & heat resistant buna-n material. Kits inlude 4 o-rings.
 
3mm x 124mm for use on all 8lug center caps
3mm x 101mm for use on most 5 & 6 lug center caps from 4.250"-4.559" diameter
3mm x 87mm for use on all 3.50" bore center caps