This is a replacement valve cover grommet kit for the AP basic valve cover hardware kit.  THIS WILL ONLY WORK WITH OUR KIT. 

This configuration is the latest revision using rounded grommets to work better with valve covers that have excessively thick paint / powder coating in the pockets for the hardware.  Using a square profile grommet worked great until the edges of the valve cover fastener pockets are filled with excess paint / powder coat build up. This thick coating could cause bulging of the grommet that will not affect function but may appear less than ideal. The round edge allows the grommet to expand better without bulging.

All new kits are also shipping with a revised round o ring / flat grommet (for the 2 screws in the spark plug valley) configuration,

If you have the old square profile configuration, It will work fine and there is no reason to replace unless they are getting deformed from age / mileage.