Specifications: The thermopile is used with 750 millivolt pilot systems. This formula is usually discovered on gas fireplaces and gasoline logs that use wall switches or remote controls. This equipment is a kind of cobination form thermocouple, affords energy for 250/750 millivolt self-generation management systems. a. Internal resistance (25°C), varies with specs and size between 1,500 mΩ and 4,500 mΩ. b. Normal working temperature 700-750°C. c. Connecting type: spiral variety and two-pole plug-in type. d. Length 36 inch Type: Gas Water Heater Parts Material: copper color:picture coloration Features: corrosion resistance, hot temperature resistanceApplicable gas: natural gas / liquefied petroleum gasApplication areas: gasoline ovens, gas grills, fuel boilers, gas water heaters, etc. Package Contents: 5 * thermopile Only the above kit content, other merchandise should not included. Note: Light capturing and varied exhibits could cause the color of the thing within the photo a bit of different from the real thing. The dimension allowed error is +/- 1-3cm.