Features:Insulatsion, high corrosion resistance, scratch proof and Good chemical stability.Mainly used in electric heating elements, protection sheaths, insulators and fish beads for temperature sensors. Specification:Material: CeramicHole Diameter: 6.2mm / 0.24 inchInner Diameter: 18mm / 0.71 inchTotal Size: 27.5 x 34.5mm / 1.08 x 1.36 inch (H*Outer Dia) Package Content:5pcs x Ceramic Insulator