Wireless system by built in Li-on battery (No electricity connection required when use). Low heat & low noise even long operation. 3 grades of light intensity control in right / center / left side: High, Medium, Low. Fast whitening by using 3 pcs of 5W L.E.D. Effective cooling system with silent fan. Lightweight & easy to assemble. Easy control length of pole and arm. Recharging the battery pack by adapter and NO electricity outlet and wire is needed after recharging. Autoclavable soft mouthguard included. Compact packing to reduce delivery cost.