PATENTS

12 Months Ended

Sep. 30, 2021

PATENTS

6. PATENTS

6.	PATENTS
	Patents consist of the following at September 30:

	2021			2020
Patents	$	910,523		$	896,372
Accumulated amortization		(634,657	)		(582,950	)
Patents, net	$	275,866		$	313,422

During the years ended September 30, 2021 and 2020, there was no impairment of patent costs. Amortization expense for the years ended September 30, 2021 and 2020 totaled approximately $52,000 and $53,000, respectively. The total estimated future amortization is as follows:

Years ending September 30,
2022	$	49,000
2023		39,000
2024		31,000
2025		29,000
2026		25,000
Thereafter		103,000
	$	276,000