SC Precision are not just another round commodity rail button..... these are precision CNC machined from black Delrin to a true NACA airfoil shape.  This allows for easier mounting on the rail and aerodynamics are improved over the round versions.  A low profile of 0.320", and maybe best of all they just look FAST! Comes with a pair of buttons and two 8-32 x3/4" Socket Flat Screws.