GEMS Sensors, Inc 170234Product Attribute Attribute Value Series FS 500 Series Overview The FS 500 offers low cost flow monitoring with a variety of switch actuation points and low pressure drop. All wetted parts are polypropylene or stainless steel, making this switch ideal for a wide range of chemical and temperature requirements. The materials are also NSF or FDA approved for potable water treatment applications including chlorinators, purifiers and heaters. The FS 500 is