The ACI Platinum Outside Air Series features a weather proof European style, plastic enclosure with twist off cover and water tight cord grip. The sensing element contains Etched Teflon colored lead wires to differentiate the sensor types. The three-wire “-3W” option should be ordered if using with a 3-Wire temperature transmitter or sensor configuration on your building management system or PLC (Programmable Logic Controller). The purpose of the 3rd wire is to compensate for external lead wire resistance that will affect your sensors output signal. ACI recommends the use of 18 AWG lead wires to reduce external lead wire resistance when using a Platinum RTD sensor. The sensors in this series are manufactured using ACI’s proven double encapsulation process to eliminate the effects of moisture on the sensor and to increase response time using our high quality, thermally conductive epoxy. The outdoor air sensor is a single point sensor designed to be mounted under an eave or on the North side of a building in a shaded location with the sensing tube pointed downward. Optional NEMA 4X “-4X” plastic or NEMA 3R “-BB” weatherproof Aluminum enclosures and NIST Certificates are available as referenced on the back of the product data sheet.  For Applications in which the sensor must be mounted in direct sunlight, please see the Sun Shield data sheet which will allow you to order a Temperature or Temperature/Humidity Combination sensor. Applications: Outside Air Temperature Sensing, Cold Storage Facilities, High Dew Point/Condensing Environments