Sheffield Company specializes in manufacturing a unique model of bicycle helmet. The model is well accepted by consumers, and the company has enough orders to keep the factory production at 10,000 helmets per month ( 80% of its full capacity). Sheffield's monthly manufacturing costs and other expense data are as follows. Cost Item Rent on factory equipment Insurance on factory building Raw materials used (plastics, polystyrene, etc.) Utility costs for factory Supplies used for general office Wages for assembly-line workers Depreciation on office equipment Miscellaneous materials used (glue, thread, etc.) Factory manager's salary Property taxes on factory building Advertising for helmets Sales commissions Depreciation on factory building Materials Labor Overhead $ $ $