Pinch Flats:
A term describing holes in the inner tube of the tire created when the tire makes forceful impact with sharp objects (e.g., rocks, ledges, etc.), causing the tire to quickly compress, "pinching" the inner tube between the hard edge of the wheel and the object causing the impact. Chances of pinch flats increase with underinflated tires or when tire is carrying more weight.
Anti Pinch Flat (Pat. Pending)
Specially shaped material added onto the lower external and internal side of the tire sidewall to "cushion" the impact and prevent the inner tube being pinched between the edge of the rim and the object causing the impact.