This enables you to determine how many instances of a non-serialized Non-serialized Inventory items are small parts that are generally indistinguishable from one another. Items received from different vendors are assumed to be interchangeable for filling any part request. Non-serialized items can be sold and tracked in fractional quantities up to four decimal places (i.e.: 43.3082 widgets). Because non-serialized items are interchangeable, ServiceCEO supports several costing models for estimating the cost of a given item when sold. inventory item you will use for a job. Simply type the number of units you want to use on the job and click Save. The Inventory Source Screen appears.