GEOGRAPHIC INFORMATION (Details) - Geographic information regarding net sales - USD ($)	12 Months Ended
	May 31, 2021	May 31, 2020
Revenues from sales to unaffiliated customers:
Net Sales	$ 7,199,027	$ 6,692,711
Net Sales Percent	100.00%
Europe [Member]
Revenues from sales to unaffiliated customers:
Net Sales	$ 4,301,000	2,434,000
Asia [Member]
Revenues from sales to unaffiliated customers:
Net Sales	1,908,000	1,867,000
UNITED STATES
Revenues from sales to unaffiliated customers:
Net Sales	548,000	445,000
South America [Member]
Revenues from sales to unaffiliated customers:
Net Sales	250,000	1,615,000
Middle East [Member]
Revenues from sales to unaffiliated customers:
Net Sales	192,000	314,000
Other [Member]
Revenues from sales to unaffiliated customers:
Net Sales		$ 18,000
Geographic Concentration Risk [Member] | Revenue, Segment Benchmark [Member]
Revenues from sales to unaffiliated customers:
Net Sales Percent	100.00%	100.00%
Geographic Concentration Risk [Member] | Europe [Member] | Revenue, Segment Benchmark [Member]
Revenues from sales to unaffiliated customers:
Net Sales Percent	60.00%	36.00%
Geographic Concentration Risk [Member] | Asia [Member] | Revenue, Segment Benchmark [Member]
Revenues from sales to unaffiliated customers:
Net Sales Percent	26.00%	28.00%
Geographic Concentration Risk [Member] | UNITED STATES | Revenue, Segment Benchmark [Member]
Revenues from sales to unaffiliated customers:
Net Sales Percent	8.00%	7.00%
Geographic Concentration Risk [Member] | South America [Member] | Revenue, Segment Benchmark [Member]
Revenues from sales to unaffiliated customers:
Net Sales Percent	3.00%	24.00%
Geographic Concentration Risk [Member] | Middle East [Member] | Revenue, Segment Benchmark [Member]
Revenues from sales to unaffiliated customers:
Net Sales Percent	3.00%	5.00%
Geographic Concentration Risk [Member] | Other [Member] | Revenue, Segment Benchmark [Member]
Revenues from sales to unaffiliated customers:
Net Sales Percent	0.00%	0.00%