Big Boomer blocking sleds from Fisher give players a realistic fulcrum pivoting action so they can achieve leveraged power over an opponent without losing their balance. Coaches choose this product because this sled is completely customizable by adjusting spring tension, pad height and pad angle. The pad height and three pad angles are adjustable with a single pin to put the player in a good football position.Each blocking unit is made up of "pigs" and pads. The "pig" is constructed with a high strength 1/4" steel plate, double welded for maximum strength and durability. The "pig" attaches to the steel chassis and is fully adjustable. The spring tension adjustment is an integral part of each "pig". The pad fits onto the "pig" and is fully adjustable. All metal surfaces are powder coated to prevent rust.Each Boomer sled pad has a core that is built from high density, 100lb impact resistant foam. The durable 18oz vinyl covers are then double and triple stitched to withstand harsh weather and years of hard use.