In assemble$-$to$-$order $($ATO$)$ production:

a$.$ the finished product is generally a combination of common components and a limited number of options or accessories made available to the customer.

b$.$ the finished product is a combination of standard and custom$-$designed components that meet unique needs of a specific customer.

c$.$ highly tailored products are created for the customer whose specifications require unique engineering design or significant customization.

d$.$ customer orders are filled from finished goods inventories, and production orders are used to replenish finished goods inventories.