The Fischer DuoPower offers very good hold values as a result of its 2 components Depending on the building material, the grey components made from high quality nylon automatically activates the optimum product function (expansion, folding, knotting) for the best hold The expansion wings of the red component support the secure expansion and offer additional security to the grey component Easy screwing-in of the screw and correct "tightening" to close No over-tightening of the screw The pre-shaped edge on the plug head prevents the plug from slipping into the drill hole The nylon coated round hook screws provided are optimally suited to the Fischer expansion plug DuoPower Great feedback (feel-good factor) of the plug. You can feel exactly when the plug is installed perfectly The serrated anti-rotation feature prevents rotation in the drill hole during installation