[Lifelong free exchange service]: Jaw Exerciser device belongs to consumer goods, and it is normal that it is damaged during use. If you buy our Jaw Exerciser, we will provide you with free exchange service for life until you get a perfect face shape. If you have any questions, please contact us immediately and we will give you a reply within 24 hours. ^[Perfect Jawline Shape] say goodbye to double chin and relaxed facial muscles. By eliminating the fat deposition around the chin and neck, the jaw exerciser promotes facial firmness and chin lift, and creates a perfect chin contour. ^[Repair Flabby Skin] If you have facial skin laxity after weight loss or childbirth, , please choose our jaw exerciser for men and women. It can enhance the blood flow of face and neck muscles by training 55 facial muscles, reshape your face shape, and make your skin tighter and stronger. ^[Correct Training]: firmly bite a Jaw Exerciser with your back teeth for 10 seconds (If your mouth is not big enough, please use a single), feel the muscle exerting force, and then relax. Repeat 6-8 times in a minute, Train 5-10 minutes a day. Please do not chew fast, but bite with teeth, feel the muscle in the force. If the product is worn out because the back teeth are too sharp, please contact us and we will provide you with a refund. ^[Food Grade Quality] the jaw exerciser are made of food grade materials without any chemical fillers or by-products, so they are very safe to chew. It's made of the same material as a baby pacifier. It's elastic and not easy to deform. You can rest assured to exercise.