Different types of businesses will need different item classes for their inventory items. Your business may need more than one kind depending on what type of business you have. 
 Service business
Service business
                Since you sell services, such as maintenance contracts, you will most likely want to set up:
 Retail
RetailIn this type of business where you stock and sell inventory items, you are most likely going to want to set up:
 Manufacturing business that builds products
Manufacturing business that builds products
                In a manufacturing business that builds and sells products from raw materials, you will most likely want to use the following item classes:
 Professional business that tracks time and expenses
Professional business that tracks time and expensesA law firm or other professional organization that bills customers based on time and expense would most likely want to set up and use the following item classes:
 Construction company
Construction company