Inventories (Details) - USD ($)	Sep. 30, 2021	Jun. 30, 2021
Inventories
Work-in progress	$ 784,595	$ 829,962
Component parts	8,662,356	8,994,457
Finished goods	1,661,353	1,800,461
Reserve for obsolete and excess inventories	(2,174,149)	(2,174,149)
Inventories	$ 8,934,155	$ 9,450,731

Amount of inventory reserves for last-in first-out (LIFO) and other inventory valuation methods.

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Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of merchandise or goods in the production process expected to be completed within one year or operating cycle, if longer.

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Amount before valuation and LIFO reserves of other supplies used within the manufacturing or production process expected to be consumed within one year or operating cycle, if longer.

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