Note 7 — Intangible assets, net

Intangible assets, net consisted of the following (in thousands):

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Amortization expense was $366,000, $809,000 and $937,000 for the years ended December 31, 2023, 2022 and 2021 respectively. The estimated aggregate amortization expense expected to be recorded in respect of these assets for each of the five years ended 2028 is $216,000, $114,000, $13,000, $1,000 and $nil, respectively.