A synthetic polyester wax with a very low melting point (37°C). Invented by Dr. H.F. Steedman, as a ribboning embedding medium. Its main advantage over paraffin and ester waxes is its low melting point, which reduces tissue hardening, shrinkage, and eliminates the need for infiltration ovens.
The wax is soluble in most organic solvents, including alcohol, ethers, esters, ketones and hydrocarbons. The wax is water tolerant, almost opaque, and sections easily. No electrification of ribbons occurs during sectioning. Sections of 2 microns and more may be cut at room temperatures between 10 and 22°C. It is advantageous to keep the wax in its solid state prior to use.