Statements of Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net sales	$ 3,279,399	$ 3,885,887	$ 6,459,716	$ 7,322,151
Costs and expenses:
Cost of sales	1,467,323	1,536,842	2,755,668	2,904,525
Operating expenses	502,094	534,420	1,049,056	1,058,534
Research and development expense	93,846	91,285	192,504	192,949
Total costs and expenses	2,063,263	2,162,547	3,997,228	4,156,008
Income from operations	1,216,136	1,723,340	2,462,488	3,166,143
Other income (expense):
Investment income	49,941	57,777	94,108	104,559
Net gain (loss) on marketable securities	86,849	(18,256)	344,043	(153,406)
Loss on trade-in of equipment				(12,837)
Total other income (expense)	136,790	39,521	438,151	(61,684)
Income before provision for income taxes	1,352,926	1,762,861	2,900,639	3,104,459
Provision for income taxes	274,116	370,199	599,135	651,935
NET INCOME	$ 1,078,810	$ 1,392,662	$ 2,301,504	$ 2,452,524
Earnings per common share
(Basic and Diluted) (in dollars per share)	$ 0.23	$ 0.30	$ 0.50	$ 0.53
Weighted average shares
(Basic and Diluted) (in shares)	4,594,319	4,594,319	4,594,319	4,594,319