the u shape groove the offset works in conjunction with the upper component center placement cavity to give the two magnets a continuous magnetic attractive force towards one another holding the upper component in a constant lock position inside the u shape groove north pole and south pole end of the magnets facing each other the lower base component magnet cavity contains a base magnet shielding fig2 6 the shielding first goes inside the cavity before the neodymium magnet does the magnet sits on top of the shielding the purpose of the magnet shielding is to reduce any magnetic interference to the firearm bolt carrier assembly movement abstraction to the bolt carrier assembly can cause miss firing of the firearm the magnet shielding can be made of steel iron metal alloy or material which can block or absorb magnetic field fig5 18 illustrates the m lok lower base component that is designed to fit into the m lok slot rail system the upper component and the u shape groove on the base component are the same in design as shown on fig1 the only change is the m lok lower base mounting structure the screws and nuts are designed in a unique and specific way to only work with the m lok slots fig5 19 is a detail m lok locking mechanism diagram fig6 20 illustrates the keymod lower base component that is designed to fit.