1. The alumina tubes are widely used in thermocouple protections and some are used in
furnaces.
2. We could design both open for two ends, and one open, the other closed.
Also we could make with 2 or 4 holes in the tube. The size ranges
from 3mm to 600mm for O.D.,
and the length is from 1mm to 2000mm. We can also design upon the customers' detailed requirements.