AEM 150 PSIg MAP Brass Sensor Kit (Includes 150 PSIg Brass Sensor & 12in Flying Lead Connector)There are many different tools that can be used for measurement, but the degree of accuracy is dependent upon the tool. For example, a ruler can measure distance with a good degree of accuracy, but for a more precise measurement a caliper should be used. The difference between a brass pressure sensor and a stainless steel pressure sensor is similar if we think about it in these terms: Brass body, with high quality sealing which makes it impervious to