4.INVENTORIES

Inventories consist of the following:

 

 

The increase in inventory is due to continued manufacturing and receipt of our AC5 in preparation for commercialization and product rollout. There was  no reserve as of September 30, 2019. Included in research and development expense for the three months ended June 30, 2020, is an increase to the inventory reserve of  $45,945 which is attributable to required product testing during the manufacturing process. Included in research and development expense for the nine months ended June 30, 2020 is an inventory reserve of  $95,637. In determining net realizable value, appropriate consideration is given to obsolescence, excessive levels, deterioration, and other factors in evaluating net realizable value.