Schedule of Inventories (Details) - USD ($)	Jan. 31, 2022	Apr. 30, 2021
Inventory Disclosure [Abstract]
Raw materials	$ 5,656,000	$ 4,399,000
Work in process	692,000	457,000
Finished goods	914,000	768,000
Inventory in transit		173,000
Inventory gross	7,262,000	5,797,000
Less: allowance for obsolete inventory	(404,000)	(175,000)
Inventories, net	$ 6,858,000	$ 5,622,000

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