The King Instrument 7520 / 7530 series rotameters feature horizontal mounting connections for ease of installation and panel-mount capability. Utilizing a float and tapered tube design, these variable area flow meters have longer, more linear scales, better pointer stability, and greater accuracy than competitively priced products .

Precision machined from durable cast acrylic stock, these King rotameters have brass or 316L stainless steel internal components and fittings. King flow meters are available in a variety of scales for increased accuracy and repeatability; these range from 2 to 10 inches (50 to 250mm). The 7520 model is supplied without a valve, while the 7530 includes an optional control valve .

Flow capacity ranges from 7GPH to 20GPM for water and 2.6 SCFH to 60 SCFM for air. Maximum pressure is 125 psig for water and 100 psig for air. Maximum temperature is 130°F (54°C) for liquids and 100°F (38°C) for gases, with an ambient temperature range of 33 to 125°F (1 to 52°C). The standard turndown ratio is 10:1 unless otherwise indicated .