Customer relationships
Brand names and trademarks
Manufacturing designs and core technology
Non-compete undertakings and other
Total acquired intangibles
£m
£m
£m
£m
£m
Cost:
At 1st January 2019
57.1
187.3
56.0
20.2
320.6
Exchange and other adjustments
(3.0)
(7.8)
(2.2)
(0.9)
(13.9)
54.1
179.5
53.8
19.3
306.7
Acquisitions
34.9
14.3
7.2
3.8
60.2
At 31st December 2019
89.0
193.8
61.0
23.1
366.9
Amortisation and impairment:
At 1st January 2019
25.1
21.3
14.2
15.6
76.2
Exchange adjustments
(1.3)
(1.1)
(0.6)
(0.8)
(3.8)
23.8
20.2
13.6
14.8
72.4
Amortisation and impairment
7.1
10.4
5.6
3.7
26.8
At 31st December 2019
30.9
30.6
19.2
18.5
99.2
Net book value:
At 31st December 2019
58.1
163.2
41.8
4.6
267.7

text: 15 Goodwill and other intangible assets continued
text: Acquired intangibles
text: The disclosure by class of acquired intangible assets is shown in the tables below.
text: 2019
text: Customer relationships are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. Within this balance individually material balances relate to Thermocoax £32.6m. The remaining amortisation period is 14.3 years.
text: Brand names and trademark assets are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. Within this balance individually material balances relate to Chromalox £114.1m (2018: £125.4m), Gestra £28.4m (2018: £32.5m) and Thermocoax £13.6m. The remaining amortisation periods are 17.5 years, 12.3 years and 19.3 years respectively.
text: Manufacturing designs and core technology are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. Within this balance individually material balances relate to Chromalox £12.9m (2018: £15.1m), Gestra £10.8m (2018: £12.3m) and Aflex £8.5m (2018: £9.4m). The remaining amortisation period is 12.5 years for Chromalox, 12.3 years for Gestra and 10 years for Aflex.
text: Non-compete undertakings are amortised over their useful economic lives in line with the accounting policies disclosed in Note 1. There are no individually material items within this balance.

Questions:
question: How are non-complete undertakings amortised?
answer: amortised over their useful economic lives in line with the accounting policies disclosed in Note 1
question: What do the individually material balances within the balance of brand names and trademark assets after amortisation relate to?
answer: Chromalox
Gestra
Thermocoax
question: What are the different classes of acquired intangible assets in the table?
answer: Customer relationships
Brand names and trademarks
Manufacturing designs and core technology
Non-compete undertakings and other
question: Which class of acquired intangible assets shown in the table has the lowest amount of acquisitions?
answer: Non-compete undertakings and other
derivation: 3.8<7.2<14.3<34.9
question: What was the change in the amount of individually material balances under manufacturing designs and core technology for Aflex in 2019 from 2018?
answer: -0.9
derivation: 8.5-9.4
scale: million
question: What was the percentage change in the amount of individually material balances under manufacturing designs and core technology for Aflex in 2019 from 2018?
answer: -9.57
derivation: (8.5-9.4)/9.4
scale: percent