The is element type is manufactured by a slightly different process than the standard rod Sic elements called reaction bonding and this process produces a much higher density material with chemical attack resistance and high mechanical strength.
This type has a central spiral groove cut to form the heating zone, withstands higher temperatures than type E and F, and has high corrosion resistance, thus shows excellent performance in severe service conditions. Use of the types SG and SGR is recommended for the applications where service conditions are severer or where the temperature in the furnace chamber exceeds 1400°C.