Sponge is an armchair with distinct folds that result from a process in which the leather upholstery is filled with polyurethane foam instead of the more traditional manufacturing process in which the upholstery is the last thing to be applied, a process that causes the leather to fold with an irregularity that both gives character and makes each piece unique. To maintain its structure before the foam solidifies, there is an internal steel frame that reinforces the construction. Sponge, as the name suggests, can be likened to a scrubbed sponge. The upholstery is offered in a wide variety of leathers in assorted colors and pricing, including a gold version.