Programmable natural convection 99L dry heat sterilizer with independent overheat prevention device. High precision controller with improved display visibility and operability. Standard equipped with calibration off-set, lock function, power recovery mode, power on and operation time accumulation, calendar time, accumulation power consumption monitoring, total CO₂ emission, and heat output, save and access operator setting information. Maximum 99 steps, 99 patterns, repeat operation. Easy sample data collection with cable port. Temp setting range ambient +5~260 C.