PRODUCT WARRANTIES (Details) - USD ($)	3 Months Ended	9 Months Ended
Feb. 28, 2023	Feb. 28, 2022	Feb. 28, 2023	Feb. 28, 2022
PRODUCT WARRANTIES
Balance at the beginning of the period	$ 311,000	$ 415,000	$ 410,000	$ 494,000
Accruals for warranties issued during the period	84,000	37,000	207,000	294,000
Adjustments to previously existing warranty accruals	0	26,000	61,000	98,000
Consumption of reserves	(107,000)	(108,000)	(390,000)	(516,000)
Balance at the End of the period	$ 288,000	$ 370,000	$ 288,000	$ 370,000

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- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for estimated claims under standard and extended warranty protection rights granted to customers.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.15(5))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(1)
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-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (c)(5)
-URI https://asc.fasb.org/extlink&oid=126907703&loc=d3e12565-110249

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- Definition

Amount of decrease in the standard and extended product warranty accrual from payments made in cash or in kind to satisfy claims under the terms of the standard and extended product warranty.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph ((c)(2))
-URI https://asc.fasb.org/extlink&oid=126907703&loc=d3e12565-110249

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Amount of increase (decrease) in the standard and extended product warranty accrual from changes in estimates attributable to preexisting product warranties.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
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Amount of increase in the standard and extended product warranty accrual from warranties issued.

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-Name Accounting Standards Codification
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