Triple-walled with an inner chamber, outer wall, and steam jacket made of thick stainless steel sheet. The lid is made out of stainless steel plate and is closed by a wing nut arrangement. The jacket is insulated by high-grade glass wool to minimize temperature loss. All sterilizers are hydraulically tested up to 2.5 times their working pressure. The instrument is fitted with a pressure switch to control the pressure in the chamber. The sterilizer is fitted with a safety valve, a water level indicator, and water inlet and drain valves. The sterilizer is supplied complete with cord and plug. The instrument is designed to operate on a 220V AC supply (a model with 110V is also available).