The Z-9 Milled Model 2 putter head is 100% milled a block of 6061-T6 aircraft grade aluminum. A heavy brass back weight which also serves an alignment aid makes up over 50% of the head's overall weight. The rich blue anodized finish and fine horizontal milled face offer top quality for players looking for consistency putt after putt. Straight-in, face-balanced, center-shafted design. Recommended putter shaft #2178.