Tube furnace LB-20TF is a box type table top unit with provision of gas insertion. PID digital controller installed at the base of chamber controls heat temperature, air flow, pressure and speed. Selection of tube material depends on the vacuum status and temperature. FeCrAl alloy molded heating element provides intermediate electric resistance and withstand high temperature. Safety devices include ELB (elastic load balancing) and overheating protection system for end user safety.