Inventories: Inventories (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Details
Raw material	$ 2,734,512	$ 2,245,709
Work-in-process	2,081,169	1,410,868
Finished goods	2,095,279	2,096,717
Inventory, gross	6,910,960	5,753,294
Valuation reserves	(599,000)	(600,000)
Inventories, net	$ 6,311,960	$ 5,153,294

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 raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

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