Great for firing enamels and Art Clay™ Silver, but not large enough to hold the firing pan required for COPPRclay and BRONZclay.
To adjust the temperature, you can move the lid off-center or purchase an in-line controller (purchased separately - normally used by people turning the temperature down to 800 F for Keum-boo). A digital pyrometer can be used for exact temperature measurement, but is not normally necessary.
The manufacturer provides excellent instructions in PDF format for using this kiln, including specifics for fusing glass, and firing PMC+, PMC3, PMC Onfire Sterling, Art Clay 650, FYI Fine Silver, FS999 Fine Silver, EZ960, Keum-Boo, and Cork Clay. (Plus they add new instructions periodically.)