The bearing frame of the base is made of calendered metal profile and warm painted. The padded backs are made with a bearing frame in steel tubes and foams of polyurethane swaged by tapping in appropriate moulds; they are upholstered with synthetic wadding and lininigs for removing the upholsteries. The backs with wooden slats are fixed directly to the base with appropriate joints and grooves in plastic materials. On the backs upper perimeter is fixed a thick leather strap with elastic studs which bind each laminated wood flexible slat.