They are normally used for general purpose, and they are sorted in two types as mercury and organic liquid. Mercury-in-glass thermometers' measuring range is between -50 to 600 degree C, and organic liquid-in-glass thermometers' range is between -100 to 200 degree C coding with red or blue color. The length could be varied according to customers' requirements. Product Name: Round pipe Glass Thermometers Place of Origin: China Features: 1)The Metal Sleeve could be made as two types as straight and angle 90 degree 2)The material are available in nickel-chromium(A3 steel), Brass or Stainless Steel 3)The Thread of 1/2" BSP, NPT, BSPT or M20X1.5 etc, or as customer's request. 4)The Metallic Thermometer with a protective metal sleeve is designed to use with boilers or equipments directly.