Bobby Grace V-Foil MOI M6.4K. MacGregor V-FOIL MOI Putters are 100% milled from a solid block of 6061-T6 aircraft aluminium and enhanced with Tri-Tech Adjustable weighting. The combination positions the centre of gravity in the optimal position - deep and directly behind the putter face. The result: unbeatable stability and forgiveness, reduced skipping at contact and pure roll.