The L2 Putter is U.S.G.A. and R&A conforming.
Yes, the L2 can stand freely behind the ball without penalty.
The average putter lie angle is 70 to 71 degrees. This lie angle helps to get the arms closer to the body in an effort to stabilize the small light putter. The high stability of the MOI MAXX allows you to hang your arms down under your shoulders for a freer pendulum motion. This produces an arm position that works better with the more upright,(73 degree), lie angle of the MOI MAXX.
The size and weight of the L2 is what gives it such unmatched performance. Spreading weight over size, especially away from the axis of rotation, (the shaft), produces an impact area that will maintain face direction and transfer the desired energy into the ball no matter where it is contacted in this area.
A sweet spot is just a spot located in the middle of the face where face direction and impact feel will be at its optimum. So the L2 also has only a sweet spot as well. However, because of the High MOI of the L2 head, the same preferred ball response can be accomplished in a larger area that simulates the sweet spot contact. We call this the preferred impact area or sweet spot zone.
Surprising enough, hitting the ball seems to be experienced mostly on the green. When we use our clubs from tee to green, We use stroke size to determine distance. Form a full swing with the driver to a small stroke with a wedge, the stroke size determines our distance control due to the momentum we create with our motion. However, on the green, our need for extreme accuracy causes us to reduce back swing to increase our chances of hitting the ball with the small sweet spot and unforgiving face oscillation the the average putter offers us. The result is the need to generate energy in a short distance which means using more muscle and joint input in order to do so. This means using fingers hands and wrist power, mostly provided by our dominant hand, to get the ball to travel the necessary distance for the putt. The more muscles and joints you use in a stroke, which is now a hit, the more variables you bring in. Energy derived from stroke size allows for a momentum filled motion that uses gravity, which is a constant), to supply the energy needed for the distance which is more repeatable and Adrenalin proof.
M.O.I. or Moment of Inertia, is a physics term that describes the resistance of an object to twist around its axis as it moves. The higher the MOI, the more stable the object will be in relation to rotation around its center, in the case of a golf club it would be the shaft. MOI is a big deal for any club not just the putter. That is why big head drivers replaced the small persimmon head drivers of old. spreading out weight over a larger mass gives a larger heavier driver more impact area which means you can swing harder at the ball and still be reasonably accurate. For putters, it is a big game changer.