Property, plant and equipment consist of the following:

Depreciation expense was $2.9 million and $2.3 million, respectively, for the three months ended  June 30, 2025 and 2024 and $5.9 million and $4.6 million, respectively, for the six months ended  June 30, 2025 and 2024. Depreciation expense related to our manufacturing facilities and equipment is included in cost of sales and depreciation expense associated with administrative facilities and office equipment is included in selling, general and administrative expense within the accompanying condensed consolidated statements of operations.

At June 30, 2025, a total of $1.3 million of property was classified as assets held for sale within other current assets on the accompanying condensed consolidated balance sheets related to several buildings in Zhongshan, PRC. At  December 31, 2024, a total of $2.1 million of property was classified as assets held for sale within other current assets on the accompanying condensed consolidated balance sheets related to property in Glen Rock, Pennsylvania and several buildings in Zhongshan, PRC.