XXIO Eleven Half Mallet Putter Premium feel. Premium performance. XXIO Mallet Putters are forged from soft 303 stainless steel and feature tungsten weights in the toe and heel for better results on the green. Precision Milled Milled from a single billet of forged 303 stainless steel, XXIO putters offer a stable putting platform with premium feel. High Density Tungsten Nickel Weights Tungsten weights in the heel and toe expand MOI for more stability and consistency on the green.