I can't stand diapers on race cars. Most NC's have a diaper around the power steering reservoir due to leaks. To remedy this, we had custom Buna gaskets made to eliminate the need for the diaper and stop the leaking.
The gasket fits inside the OEM cap so the gasket works with the OEM power steering reservoir as well as the Aluminum Moroso tanks that many use.
The gasket is custom cut to press fit inside the OEM cap, so once it is in place it won't fall out or leak.