The  primary elements of zero inventories synonym to JIT ) are:

a. To have only the  required  inventory when  needed.

b. To improve  quality to zero  defects.

c. To reduce lead times by  reducing set up times  queue lengths  and lot sizes.

d. To incrementally revise the operations  themselves and to accomplish  these  things at minimum cost.

The  concept  of  JIT is  extended to the whole  system of production  i ,e, :

a. To produce and deliver finished goods just in  time to be sold.

b. Sub assemblies just in time to be assembled into finished goods.

c. Purchased materials just in time to be transformed into fabricated parts.

Thus JIT  standsfor producing  necessary units in necessary quantities at the necessary time. The  ultimate aim of  JIT  is to  concentrate on lotless repetitive  manufacturing  with only one unit  of work in process and no stock  of finished  goods  inventories.