Suhn’ta’lock is a Nether Lord under Azazel, and can be found in the Book of Azazel by EA Koetting.
Enns come from the religious practice of demonolatry, and In EA’s particular system of evocation, they are not generally used. Instead, conjurations are spoken, and the spirits are commanded to come forth.
A lot of people make the mistake of assuming every demon has an enn and that enns are a necessary requirement for evocation, but they are not. You can call Suhn’ta’lock easily without one. All that is needed is his seal. I do recommend EA’s Incantation to Summon Forth though. It’s powerful and works for almost any entity.