Atlas Billiards Supply. It's Aegis-II tube. It's actually a linen melamine, not phenolic. But it looks like phenolic with a white color instead of black or some shade of brown. They also sell Ivorine-4 but it's in rod form, considerably more expensive & reportedly very hard to work with. I don't know much about it.
gimme a call davebrent what do you use to part off iv4. i want to try some in lower end cues. but i hear horror stories
dave schmelke just sent me some white stuff rod form hard but not like iv4 but isnt porus like ageusII. supposed to maching easy and play hard and stay clean... havent tried it yet