This is an under-insole made using PORON. This is the 5mm thick type. This product solves the problem of: "I like my shoes and insoles, but I want to improve the shock absorption and cushioning a little more." You can improve the shock absorption and cushioning by simply placing it under your existing insole. Since it is held down by the insole, it is unlikely to slip inside during use or while playing sports, but if you are concerned, please secure it with double-sided tape in a few places. It is made in a 28cm size, but for those with sizes less than 28cm, you can use it by overlapping your existing insole, aligning the heel edges, marking the protruding toe area with a pen, and cutting it. This is a 5mm thick type, so it will make the inside of your shoes tighter. Please use it in shoes that have room in terms of size and foot shape. (We also offer a 2mm type that can be used with almost no change in size) You may feel a little cramped before use, but PORON will compress and conform to your weight to some extent. Also, this can be used to adjust the size of shoes with loose uppers, and in that case, you can adjust the size while also enhancing the cushioning, achieving a two-in-one effect. This is not an industrial product, but a handmade item, and it is cut from PORON sheets by hand with scissors, so there may be some waviness on the cut surfaces and marks from the marking. Please understand this in advance. There is no problem at all with use. It can be used not only to improve the cushioning of sports shoes but also for sneakers. Basically, we cannot offer discounts, but we can offer a small discount for bulk purchases. Thank you. ※Because PORON has the property of becoming a little harder at low temperatures, If the outside temperature is low, you may not feel the full effect. If you are concerned, please warm it with a heat pack before use.