... clear display, high ability of resist compression, convenience to install, protect and maintain.quartz glass tubular level gauge ... in petroleum,chemical, industries, electricity, metallurgy, papermaking etc.to measure transparent liquid level in tank and boiler.GZS ... material: high quality carbon steel or 1Cr18Ni9Ti5)back light: a,light Emitting Diode: electric power supply is 24VDC. b, ...