The holder for imaging windows is a modified version of the previously published “Abdominal imaging window stabilizer for inverted microscopes” (DOI: 10.5281/zenodo.8116199).Neodymium block magnets (20 × 4 × 2 mm) are bonded with cyanoacrylate adhesive onto the sloped surfaces on the objective-facing side of one holder component. Corresponding steel strips are attached—also with cyanoacrylate—onto the sloped surfaces on the animal-facing side of each holder component. This configuration provides flexible positional adjustment while maintaining sufficient magnetic force to securely hold the imaging window in place.Additionally, two steel strips are mounted on the objective-facing side of the stage insert. These ensure that the holder locks stably into the insert and minimize motion artefacts originating from breathing.