0303 Checkpoint Ultra-Mini G3 Oversized 0 F. vial for easy viewing. Three neodymium rare earth magnets add incredible strength to hold to any metal pipe application. Exclusive notch feature allows for attachment to pipe ends and virtually dliminates "Dog Leg" bends. The Ultra-Mini includes 0 F., 30 F. and 90 F. vial ports which are viewable from all planes. So compact (only 4 inches long), but it packs a host of features and functions for the por tradesman.