GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales - USD ($)	12 Months Ended
	May 31, 2020	May 31, 2019
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	$ 6,692,711	$ 5,200,682
Europe [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	2,434,000	1,694,000
UNITED STATES
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	445,000	523,000
Asia [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	1,867,000	2,514,000
South America [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	1,615,000	256,000
Middle East [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	314,000	214,000
Other Foreign [Member]
GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales [Line Items]
Net sales	$ 18,000