A: If you were to check out the product descriptions on each shock, you will notice the differences there. The 440 series is a little more high end, with the components and finishes used in building them. Patented Inertia Sensitive dampening 2 independent rebound damping circuits, soft (wheel) circuit and firm (chassis) circuit. Chrome and anodized billet aluminum end covers. Easily adjustable spring pre-load, no tools required. Polyurethane bushings. Powder-coat finish on the body. Black Nitride coated shock shaft, harder than chrome, impervious to rust and corrosion. Limited lifetime manufacturer's warranty on shock and springs.