The type featured is from their Ludlow section - that is, a type produced on typesetting equipment manufactured by the Ludlow Typograph Company. Wanting to offer the public a cheaper alternative to Linotype, William I. Ludlow and William A. Reade created a hot metal typesetting system.
Wikipedia provides an excellent, simple explanation for how the equipment worked:
The Ludlow system uses molds, known as matrices or mats, which are hand-set into a special composing stick. Thus the composing process resembles that used in cold lead type printing. Once a line has been completed, the composing stick is inserted into the Ludlow machine, which clamps it firmly in place above the mold. Hot linecasting metal (the same alloy used in Linotype and Intertype machines) is then injected through the mold into the matrices, allowed to cool, and then the bottom of the slug is trimmed just before it is ejected. The operator then replaces the matrices, or mats, back into the typecase by hand. Since the mats are of a consistent height, irrespective of typeface size, they are easier to handle than lead type.
Windemere, Commerce Gothic and Hauser Script were three of the Ludlow types Hazeltine offered to its customers.