1. interior of oven is made of specular stainless steel by argon-arc-welding technics and the exterior of oven is made of high-quality steel sheet with a beautiful and novel appearance. 2. microprocessor pid temperature controller with temperature control protection,digits display and timing function ensures a precise and reliable temperature control.(intelligent programable lcd temperature controller is an option) 3. hot-air circulating system consists of a fan keeping running under a high temperature and proper air ducts to ensure a uniform distribution of temperature in chamber. 4. independent alarm system for temperature-limiting ensures experiments run safely and no accident would happen.(option) 5. recorder and printer are options which can print or record set param eters and trace variation curves of temperature.(option)