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. There was no reserve as of September 30, 2019. Included in research and development expense for the three months ended March 31, 2020, is a reduction to the inventory reserve of $96,600.  Included in research and development expense for the six months ended March 31, 2020, is an inventory reserve of $49,692. In determining net realizable value, appropriate consideration is given to obsolescence, excessive levels, deterioration, and other factors in evaluating net realizable value.