This is a twin-tube low pressure gas unit (similiar to most units that would be OE your vehicle). This is a good choice for average everyday driving.

The Monroe SensaTrac unit with PSD (position sensitive damping) and the Safe Tech" system combines exclusive precision tapered grooves in the pressure tube with application engineered valving and Fluon banded piston.

The tapered grooves are manufactured into the inside of the tube of the unit where the piston travels up and down, around the middle of total travel. This allows fluid bypass, giving the unit a lighter, less dampening / valving under normal driving conditions.