IMPORTANT FAQ! Question 1: Why does it not vibrate after turning on the machine? Is it defective? Answer: It starts up without any vibration or noise, no vabration feeling in hands, that is the right working way. Actually it will NOT make any vibration and sound UNTIL touching the hard object surface like teeth, meanwhile it will automatically stop working when touch soft tissue like the tougue and gum. Question 2: Why is the strength so weak even on the high mode? Answer: Please check the following two aspects: Whether the cleaning head is installed tightenly, please use a small wrench to tighten the cleaning head. Whether the battery is about to run out. Question 3: Can I turn on the machine while charging? Answer: No, you can't turn on the machne while charging. You need to unplug the charging cable and press and hold the button for 3 seconds to turn it on in the same way, press and hold for 3 seconds to turn it off. please charge it before first-time usage.?USB Charging?Our electric teeth cleaning kit is equipped with USB-port charging ensuring full charge in 1.5 hours and continuous use of 2 hours at least, no need frequent charging, it is really easy for new users to remove stains and calculus at home. ?Versatile Dental Tools?The tartar remover for teeth is made from aluminum-magnesium alloy, built-in LED auxiliary lights, IPX7 waterproof, 4 replacement heads allow for multiple uses, 3 adjustable mode provide soft-middle-high strength, suiting various dental cleaning option. ?Safe Teeth Cleaning?The teeth cleaning kit only works on teeth and hard surfaces, automatically stop working while touching gums and soft tissue, this function enable user get safe tooth cleaning without hurting gums. ?High Efficiency?The plaque remover for teeth can effectively remove plaque and tartars, coffee stains, smoke stains and tea stains in a few minutes, adapted to almost family members and pets. ?Save Time Money?This affordable teeth whitening kits come with all necessary dental picks you need to remove plaque and calculus, better whitening effect when cooperating with daily brushing and flossing, you can make tooth cleaning at home whenever and wherever.