Paraformaldehyde, 4% in PBS + Mg + EGTA is used as a common fixative reagent for histology. It is also used to prepare pure formaldehyde.
This Thermo Scientific Chemicals brand product was originally part of the Alfa Aesar product portfolio. Some documentation and label information may refer to the legacy brand. The original Alfa Aesar product / item code or SKU reference has not changed as a part of the brand transition to Thermo Scientific Chemicals.