XDT14Z= Quick-Shift mode selector has an automatic electronic controller that downshifts and reduces rotation and impact speed prior to driving screw into place. Tightening mode (t-mode) for faster tightening of Self-Drilling screws; helps prevent damage to the screw or workpiece. BL1830B= Integrated L.E.D. battery charge level indicator allows user to monitor battery charge. Reaches full charge in 30 minutes or less. Impact-resistant outer case and shock-absorbing inner-liner are engineered to protect the battery. Offers 3.0 amp hour of runtime.