The Deep Face series from Heavy Putter features models that have a face about 1/4 inch taller than a traditional putter. This aligns the sweet spot of the putter with the center of the golf ball for more consistent rolls. There are different head shapes available, all face-balanced and high Moment of Inertia designs that fit players with a "straight-back, straight-through" putting stroke best. The D1 and D3 are both a "humpbacked" mallet design that increases the the MOI while keeping the Center of Gravity high. The E1 and E3 have a scooped out bottom for the same purpose. Removing material from the sole keeps the club from twisting and also keeps the CG in line with the center of the golf ball. The F3 is a blade that borders on mallet styling with the geometric heel and toe. The G3 has a sloped cavity to keep the CG high. Like all Heavy Putters these models have a weight in the shaft to move the balance point of the club higher to produce a more stable, pendulum-like stroke.