5. Intangibles

Trademarks are not amortized as their lives are deemed to be indefinite. Total amortization expense for each of the next five years is estimated to be as follows: 2020 - $4,082,000; 2021 - $4,062,000; 2022 - $4,055,000; 2023 - $4,055,000 and 2024 - $3,372,000.

	Industrial Hardware Segment		Security Products Segment		Metal Products Segment		Total		Weighted-Average Amortization Period (Years)
2019 Gross Amount
Patents and developed technology	$	5,375,680	$	1,618,950	$	—	$	6,994,630		10.2
Customer relationships		22,899,000		1,139,381		—		24,038,381		9.6
Non-compete agreements		12,000		459,570		—		471,570		1.9
Intellectual property		—		307,370		—		307,370		2.0
Total Gross Intangibles	$	28,286,680	$	3,525,271	$	—	$	31,811,951		9.5

2019 Accumulated Amortization
Patents and developed technology	$	1,505,097	$	789,056	$	—	$	2,294,153
Customer relationships		1,751,225		581,262		—		2,332,487
Non-compete agreements		800		417,032		—		417,832
Intellectual property		—		307,369		—		307,369
Accumulated Amortization	$	3,257,122	$	2,094,719	$	—	$	5,351,841

Net 2019 per Balance Sheet	$	25,029,558	$	1,430,552	$	—	$	26,460,110

2018 Gross Amount
Patents and developed technology	$	7,884,498	$	1,648,731	$	—	$	9,533,229		10.2
Customer relationships		3,650,000		1,139,381		—		4,789,381		8.1
Non-compete agreements		—		459,570		—		459,570		4.4
Intellectual property		—		307,370		—		307,370		5.0
Total Gross Intangibles	$	11,534,498	$	3,555,052	$	—	$	15,089,550		9.2

2018 Accumulated Amortization
Patents and developed technology	$	2,448,380	$	737,276	$	—	$	3,185,656
Customer relationships		638,750		408,233		—		1,046,983
Non-compete agreements		—		329,296		—		329,296
Intellectual property		—		245,895		—		245,895
Accumulated Amortization	$	3,087,130	$	1,720,700	$	—	$	4,807,830

Net 2018 per Balance Sheet	$	8,447,368	$	1,834,352	$	—	$	10,281,720