1. Inside size: 240*330*430 mm 2. Temperature range:-30 °c~300 °c 3. Temperature accuracy: 0.3% 4. Temperature fluctuation range: ±0.5°c 5. Temperature uniformity: ±2°c 6. Speed of cooling: 0.7~1 °c/min 7. Hollow electric heating glass observation platform 8. Temperature control: PID automatic temperature control 9. Material of outside wall: cold-rolled iron sheet spraying 10. Material of inner wall: stainless steel sheet 11. Insulation material: antiflaming insulation material 12. There are electric heating devices on the edge of doorframe and doorplate to prevent condensation and frost formation when processing low temperature test. 13. Illuminating lamp: one (damp-proof, explosion-proof, locating proper position, outside control switch) 14. Air conditioning system: a temperature control: PID automatic temperature control b air circulation device: centrifugal fan c manner of heating: nickel-chromium electric heater, forced aeration and inner circulation temperature adjustment d manner of air cooling: compressor refrigerating e temperature measuring transducer: platinum resistor f refrigerating compressor: compressor (CFCs) refrigerating (France Tecumseh hermetic fan cooling) 15. Tightness and reliability: pipeline of cooling system is welded and tightness is reliable 16. Devices for safety and protection a power supply overload and short-circuit protection b refrigerating compressor lack-phrase protection c ground connection protection d over temperature protection e refrigerating machine high and low voltage protection