Double Walled STD/GMP Model. The chamber is insulated by filling CFC free Polyurethane foam in the space between outer body and chamber to prevent temperature loss. Pilot lamps for all switches & controls, illumination provided for inner chamber with forced air circulation fan for uniform temperature throughout the chamber. Hermetically sealed compressor unit for CFC free cooling system. Temperature Range 5°C To 60°C ± 0.5°C or better. Controlled by preset dual display electronic digital temperature controller cum Indicator.