4- piston caliper "sleeving"?????

340sFastback, those look like some pretty fancy bleeders. Which one did you get, the Chrysler one? Would it also work with an older GM, or are they actually model specific?
On a side note, I have an an el-cheapo brass one from Harbor Freight. It works "OK", but nothing special and I think the brake fluid actually ate up some of the rubber fitting that it came with!
C