This is a brand new item that has never been used. Free shipping is available within Japan without exception. No comments are needed; immediate purchase is welcome. Since we are selling at the limit price from the beginning, we do not offer discounts except for irregular sales, but we will consider a discount if you purchase multiple items, so feel free to comment. This is a set of 3 pairs (6 pieces total) of upper and lower mouthpieces. There are no instructions, so please use the following 【How to Use】 as a reference. 【How to Use】 1. Warm the mouthpiece in 90-100°C (194-212°F) hot water for 5 seconds (The temperature at which it softens varies depending on the season) 2. Take it out of the hot water and let it cool for 10 seconds 3. Press it firmly against your teeth to create a mold 4. Trim off the excess with scissors and shape it ※ We are not responsible for any injuries, such as burns, caused by improper use, so please use it at your own risk. ◆Must Read◆ To reduce the burden on postal workers, shipping on Saturdays, Sundays, holidays, and the next day is no longer available. If your item does not arrive after a week from the shipping date, please contact us as there may be a delivery accident. If you would like tracking 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 your request. (We do not ship with Yu-Yu Mercari Delivery) ※ The theft of images and text infringes on intellectual property rights and violates Mercari's rules and the law, so please do not do so under any circumstances. If we find any instances, we will report them to the Mercari office and consider legal action. Teeth grinding, false teeth, 736apu028spamoto101