Note 3 - Quarterly Results of Operations (Unaudited): Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Details
Net Sales	$ 9,157	$ 10,005	$ 10,400	$ 11,340	$ 12,333	$ 12,505	$ 12,866	$ 12,520	$ 13,575	$ 12,955	$ 13,428	$ 12,323	$ 40,903	$ 50,224	$ 52,281
Gross Profit	5,323	5,802	6,253	6,766	7,098	7,359	7,739	7,843	8,327	8,186	8,151	7,533	24,143	30,038	32,196
Net Income	$ 2,902	$ 3,563	$ 3,453	$ 3,956	$ 4,287	$ 3,935	$ 4,200	$ 4,214	$ 4,555	$ 4,280	$ 4,103	$ 3,534	$ 13,874	$ 16,635	$ 16,473
Earnings per common share (diluted)	$ 0.86	$ 1.03	$ 0.98	$ 1.09	$ 1.18	$ 1.08	$ 1.15	$ 1.16	$ 1.25	$ 1.18	$ 1.12	$ 0.96	$ 3.96	$ 4.57	$ 4.52