XXIO 13 Men's Single Iron4 PIECE CONSTRUCTION XXIO 13 Irons feature a low Center of Gravity thanks to their 4 piece construction, which uses titanium faces and tungsten nickel sole weights. That weighting, combined with our unique Rebound Frame structure which alternates stiff and flexible zones for added ball speed, gives you a satisfyingly high launch with incredible distance. TITANIUM FACES The thin, high strength titanium face, along with hollow portions of the heel,