GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales - USD ($)	3 Months Ended
Aug. 31, 2020	Aug. 31, 2019
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	$ 1,143,806	$ 1,194,415
UNITED STATES
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	134,000	115,000
Asia [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	347,000	663,000
Europe [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	591,000	301,000
South America [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	43,000	47,000
Middle East [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	$ 29,000	$ 68,000

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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+ Details