OF FOUR (4) RARE VINTAGE BROWN GLAZED STEATITE CERAMIC HIGH VOLTAGE INSULATORS WITH MANUFACTURER PART NUMBER No.: 212The specifications for these components are as follows: Length: Approximately 1.500” +/- 0.05″ (37.6 mm) Outside Diameter: Approximately 0.500”+/- 0.02″ (12.7 mm)Thread Hole Depth: Approximately 0.500”+/- 0.010″ (12.7 mm)Threaded ID : M4 *12.7 mm Manufacturer Part Number: CNP NS4AB0212 You are buying ONE LOT OF FOUR (4) Rare Manufacturer Numbered CNP NS4AB0212 Vintage Brown Glazed Steatite Ceramic High Voltage Insulator. These are Rare and hard to find. They made from high purity Steatite and glazed with brown glaze. These vintage insulators were manufactured by the National Porcelain Company of Trenton, New Jersey. They are no longer in business. These vintage insulators are New Old Stock They are in mint condition. They will be great for your Steampunk or Tesla projects. Steatite/Porcelain is a low cost material with high electrical resistance at high temperatures, good mechanical strength and a very low dielectric loss factor. Such properties make it ideal for high frequency, low loss, and high voltage insulation. Moreover, steatite is an excellent material for electrical engineering as it can be readily shape sintered into a wide variety of forms such as washers, bushings, resistor forms, spaces and beads. Steatite has been used for many years in large-scale industrial systems, household electronic appliances, aerospace and automotive applications; and in specialized electro-technical instruments such as cathode-ray tubes. This material has very good corrosion resistance to chemicals and high refractoriness or use temperature. They may be used for a variety of electrical, mechanical, and thermal applications. It may be used for high temperature furnaces as thermocouple and sensor insulator tubing. It may also be used for jewelry as beads when cut small. Your imagination is the only limiting factor in the spectrum of possible applications for this component. Be sure to view all photos as they are an integral component of the item description. The specifications for these components are as follows: Length: Approximately 1.500” +/- 0.05″ (37.6 mm) Outside Diameter: Approximately 0.500”+/- 0.02″ (12.7 mm)Thread Hole Depth: Approximately 0.500”+/- 0.010″ (12.7 mm)Threaded ID : M4 *12.7 mm Manufacturer Part Number: CNP NS4AB0212 Please Note: There are visually discernible differences in any or all of the dimensions. These are not precision technical ceramic components. There is no warp or camber Specification for this item. However they are relatively straight and round. There may also be “firing” color variations inherent in the material. The thermal shock resistance is not very high so exercise rule of thumb caution. “The larger the piece of material the slower the rate of temperature increase should be applied to the piece.” Heat up slowly to avoid cracking in use. Specific Gravity or Density: 2.75 g/cm3 Water Absorption or Porosity: 0% Fusion Temperature or Melting Temperature: 1890 °C or 3434 °F Maximum Working Temperature: 1290 °C or 2350 °F Thermal Conductivity @ 25°C: 3 W/m* K Specific Heat: 0.9 J/g*K Expansion Coefficient or CTE: 8.6 x 10-6 inches/°C Bulk Electrical Resistivity at 20 C: 1014 Ohm*cm Bulk Electrical Resistivity at 700 C: 1010 Ohm*cm Modulus of Elasticity: 15 x 106 p.s.i. or 110 GPa. Flexural Strength: 20 x 103 or 140 GPa Dielectric Strength: (0.125” Thick): 270 V/mil Dielectric Constant @1 MHz: 5.7 Dielectric Constant @ 9.2 and 12.5 GHz: 5.6 -5.8 Dielectric Loss @ 1MHz: 0.003 -0.0014 Dielectric Loss @ 9.2 and 12.5 GHz: 0.005 -0.0017 These components were not specifically manufactured for an individual application; therefore be sure to check the dimensional descriptions carefully for your application. Future returns or requests for refunds, because of some “fit” issue or the like will not be honored. Please check the other Steatite component variants that are available in my listings for the model or models that best fits your requirement. Your imagination is the only limiting factor in the spectrum of possible applications for these components and materials. If you require additional technical information, design, or application engineering consultation, feel free to contact us. As a materials scientist with four decades experience in high temperature processing, ceramics, dentistry, and jewelry manufacture it will be possible to provide you with creative and imaginative approaches to your requirements. Feel free to ask any questions you may have regarding this item early. Use PayPal only. Combined shipping discount is provided for multiple item purchases. For best results, please be sure to shop using cart, then complete the paying transaction when you are satisfied that all the items you need are in the cart. Items purchased separately will be shipped separately as a unique transaction. Please complete payment transactions within 3 days. Items are generally shipped via USPS first class mail with delivery confirmation. Ask about shipping costs to your country. Feedback is provided for all buyers. We will appreciate yours as well. We strive to maintain excellent customer service; and are able to solve virtually any issues you may have. Every effort to provide the most accurate information about this item and every appropriate precaution in packaging this item is made, to assure that your highest expectations and satisfaction are met, and are exercised to meet this requirement for excellence. In winning this auction or purchasing this item you are agreeing that you will first provide the seller every opportunity to provide redress or resolution to any issues you many have concerning this item, prior to leaving any negative feedback about the seller or the item. No.: 212