Available for In-Store Pick Up One new Aero Precision lower parts kit for the AR-15 rifle. This kit comes with the takedown/pivot spring, takedown/pivot detent, takedown pin, pivot pin, bolt catch, bolt catch spring, bolt catch buffer, bolt catch roll pin, safety selector, safety selector spring, safety selector detent, buffer retainer, buffer retainer spring, magazine catch body, magazine catch spring, and magazine catch button.