When the National seal for oil bath hubs is pushed onto the spindle, the part of the seal that contacts the spindle does not rotate on the spindle. If you grab the part of the seal that would be installed in the hub, the hub part of the seal rotates. Looks like a two piece seal. The seal is made for oil bath hubs but can be used for grease.
The Dexter seal that I am replacing, works like I am used to. It rotates on the spindle.
Eloy, AZ for the winter
2015 Mobile Suites 41RSSB4
2011 F350 Dually 6.7 PSD