Made to order at 29.5 x 13.5. ***Beware of imitations!*** ★ Sold over 6,000 pieces across multiple sites! Over 500 followers! Many customers who purchased similar products from others and found the size didn't fit have purchased from me, and I have many repeat customers. Rest assured, this will fit perfectly! If you're unsure about similar products, compare the actual images, the number of followers, and the reviews. ★ This fits perfectly in the 2020 edition of the Mook book's synthetic leather bag, but please note that the 2021 edition's canvas bag is a separate listing. ★ I utilize my experience working in bag manufacturer development and constantly updated information, along with data analysis from selling 6,000 pieces, to create the perfect inner soles. ★ All items are custom-made. Millimeter adjustments are available for those who want them, and I offer techniques that mass production machines cannot. ★ Work is performed under sterilization and delivered in clean packaging. ★ I meticulously adjust and confirm everything with the bags I personally use to create the most perfect fit. This is made with a sturdy, yet lightweight, 1.5mm thick base plate specifically for the bottom of the bag. A 0.75mm thick plate can be purchased at 100-yen shops and is not recommended for genuine leather bags. I recommend this for those who want to use it properly even with Mook book attachments. Y&O leather bags have considerable individual differences. If you want fine adjustments, please measure the size yourself and specify it. Be sure to turn the bag inside out and measure: The gusset (depth) from seam to seam in the center. The width from fold to fold. If you don't specify, I will make it in the standard size. Other sizes are also supported, with a gusset up to 25 cm and a width up to 50 cm. Young & Olsen bags are made of leather and are soft, so inserting a base plate prevents them from losing their shape and is highly recommended. Also, it looks better and you can carry it neatly. Without compromising the Young & Olsen's characteristics of being lightweight and easy to use, this is a very lightweight yet sturdy base plate. Only the inner sole will be shipped. It fits perfectly in the inner groove of the Young & Olsen bag I own, but please understand that returns are not accepted if it does not fit due to individual differences in the bag.