Gravity is a slightly flexible baseline plastic that is great for putting.
The Prowler has a small bead, sort of like a P1X or Judge.
Legacy says: The Prowler is a stable, controllable beaded putter. A very predictable finish allows you to commit to chain crashing with little concern of an overthrow. A healthy bead keeps the break-in period slow and in turn makes it easy to trust its line, leaving no flight or finish surprises. Putt with Confidence.