This device is for mounting prints using either dry mounting tissue or liquid mountant. The body of the iron was heated by a gas or other burner placed in the aperture it could then be rocked over the print. A thermometer was fitted to the top of the body (broken on this example).

It was sold by Houghtons as the Ensign Dry-Mounting Outfit, where it was supplied with a stand and gas burner. At extra cost the iron was sold together with a mount cutter and zinc plates in a fitted box, an accessory spirit lamp was also offered. Advertisements suggest that it was especially suitable for mounting prints in albums.