Output Unit-level costs are the costs of activities performed on each individual unit of a product or service. Machine operations costs (such as the costs of energy, machine depreciation, and repair) related to the activity of running the automated molding machines are output unit-level costs because, over time, the cost of this activity increases with additional units of output produced (or machine-hours used). Plastim's ABC system uses molding machine-hours, an output unit-level cost-allocation base, to allocate machine operations costs to products.