Brand new, never used. Free shipping within Japan without exception. No comments needed, immediate purchase OK. We sell at the limit price from the start, so we don't offer discounts except for irregular sales, but we will consider discounts for multiple purchases, so feel free to comment. This is a set of 6 pairs (12 pieces total) of upper and lower mouthpieces. There are no instructions, so please refer to the following 【How to Use】. 【How to Use】 1. Warm the mouthpiece in 90-100 degree Celsius water for 5 seconds (The temperature at which it softens varies depending on the season) 2. Take it out of the hot water and cool it for 10 seconds 3. Press it firmly against your teeth to create a mold 4. Trim off the excess with scissors to shape it ※ We are not responsible for any burns or injuries resulting from improper use, so please use it at your own risk. ◆Must Read◆ To reduce the burden on postal workers, shipping on Saturdays, Sundays, and holidays, as well as next-day delivery, has been discontinued. If your order does not arrive after a week from the shipping date, please contact us as there may be a delivery accident. Also, if you wish to have a tracking number and anonymous shipping, you can change to "Rakuraku Mercari Delivery" for an additional 150 yen, so please write "I want Rakuraku Mercari Delivery" in the comments. We will change to Rakuraku Mercari Delivery as soon as we confirm it. (We do not ship with Yu-Yu Mercari Delivery) ※ The theft of images and text infringes intellectual property rights and violates Mercari's terms and conditions and the law, so please do not do it. If we find any, we will report it to the Mercari office and consider legal action. Teeth grinding, false teeth, 12 pieces 736 mouthpieces apu 139 spa original 104