Didn't know they were there.
Etrailer has this answer to a question on the subject.
"I spoke to my contact at Dexter and he informed me that they recommend greasing the E-Z Flex equalizers every three months or 3,000 miles. I also attached a pretty helpful guide to how often trailer components should be maintained.
For grease Dexter recommends wheel bearing grease. For that we recommend the red grease part # L11390
I'm thinking that's etrailer recommending red.
Dexters own wheel bearing grease is also Red
If it were me, I'd use the Lucas you already have.
Now I have to go do mine...