Inventories (Details) - USD ($)	Dec. 31, 2019	Jun. 30, 2019
Inventories
Work-in progress	$ 458,830	$ 288,828
Component parts	6,940,548	7,151,228
Finished goods	1,880,434	1,693,974
Reserve for obsolete and excess inventories	(1,782,753)	(1,800,935)
Inventories	$ 7,497,059	$ 7,333,095

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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