Power of Attorney for Stephen DeNelsky at Harvard Bioscience, Inc.

The filing is a Power of Attorney document for Stephen DeNelsky, a director at Harvard Bioscience, Inc. The document confirms that DeNelsky's electronic signature can be used to authenticate, acknowledge, or adopt his signature in any document electronically filed with or furnished to the SEC by him or on his behalf, or by Harvard Bioscience, Inc. This electronic signature will be legally equivalent to a manual signature. The document is dated October 6, 2025, and is addressed to the Board of Directors of Harvard Bioscience, Inc.