LRB Mattresses are flexible, resilient, easy to handle and is having low thermal conductivity which helps to control of heat loss. Operating Temp. Range-They are used at service temperatures ranging from -50 deg c to +750 deg C. Due to their flexible structure, Thermal Conductivity: Rockwool LRB Mattresses has got excellent low thermal conductivity of 0.034 W/mK at 50 C mean temperature.