The Series 11 resistance heated optical fiber drawing furnace has been sold to over 15 countries, with over 150 furnaces installed since its first introduction in 1977. The Series 11 furnace system consists of three basic components, first is the furnace which is a double walled stainless steel chamber. Inside the chamber is a highly purified graphite element and heat shield assembly. Second component is a precision control system allowing very accurate control of all critical functions of the furnace such as gas flow and temperature control. The third basic item is the power supply which consists of a silicone controlled rectifier power controller with current limiter, stepdown transformer and circuit breaker. All of the above work to allow consistent drawing of optical fiber on a repeatable basis. The Centorr/Vacuum Industries Series 11 has many additional features to consider. Many of these features gained by continual product improvement in response to our customers' needs.