They're just "boots" or "tie rod end/ball joint boots". Nothing special about them
Replacing them after they're gone isn't going to do much if you've been missing them for long. Dirt will have already found its way into the joints and ruined them, in which case replacement will be necessary shortly.
FYI: replacing the boots will NOT absolve you from needing to grease the joints regularly. If you've been greasing them every month because the boots are gone, you'd best replace the linkages soon.
JBG has some cool red ones for $5 a set too. The tie rod ends seem OK so I'll just replace the boots and see how it goes. I want a lift in the future anyway with superrunner steering or something similar.
It looks like they busted because someone put too much grease in them and they split.
I put the new dust boots on today. You guys were right about needing to replace more than the boots. i don't know how loose the ball joints should be, but 2 were very tight and jerky, while the other two were alot smoother but still stiff.
At least I got a new tool today. 16" tie rod separator from Harbour Freight - $4.99.