Description•The 444 Super Duty Series Shocks feature a proprietary patented Frequency Sensing Technology (FST) that has the unique ability to dynamically adjust damping as you ride• Whether you're hitting the small or big bumps in the road, the shock distributes oil through ports accordingly to soak up the hit making for an ultimately comfortable ride• A top mount threaded preload adjuster allows for fine-tuning with a simple twist of the cap• 444 Super-duty are designed for 350+ lbs. riders or 2 up riding totaling 350+ lbs.