The HD ( Heavy Duty version ) is especially designed for Garages, recovery businesses and other every day heavy use. They take per ramp over 2500lbs in weight compared to the 1500lbs on our standard version. Simply place the trailer door on the notch of these specially designed Trailer Ramps and decrease your angle of approach to as little as 4°. Trailer Ramps are ideal for low ground clearance cars with extra wide tyres. Use the dimensions above to determine which size fits best with your vehicle and trailer.