This item was created out of a need expressed by Mercari users. I believe you will be completely satisfied with this product. This is a Yu-Packet Post insertion confirmation tool made of cedar wood. It has 4cm and 1cm slits. The material is cedar. Cedar's unique refreshing fragrance has a relaxing effect and also has antibacterial and insect repellent properties. Wood is flexible and strong, and it becomes more polished with use, making it environmentally friendly. And the texture of the wood is superb. It is not painted. The material is approximately 14-18mm thick cedar wood. It doesn't bend like a flimsy ruler made of thin material. It's sturdy like an actual post insertion slot. You can check in advance whether you can crush and push in your package. I don't think there are any insertion measurement tools on the market with this thickness. The photos are for size and shape reference. The item to be shipped will be the same. If you would like slits for measuring other thicknesses (1cm, 5cm, etc.), please contact me via the comments on the order acceptance page. It may take some time, but I will do my best to accommodate your requests. I will use recycled packaging materials. If you purchase multiple items and they can be shipped together, I will reduce the shipping cost by at least that amount. I may change between Yu-Yu Mercari Bin and Raku-Raku Mercari Bin without notice. Thank you for your understanding. #TakawataHandmade #TakawataPackingScale #YuPacketPost4cm #YuPacketPost #ThicknessMeasurementRuler #ThicknessGaugeRuler #ThicknessMeasurementItem #ThicknessMeasurementGoods Yu-Packet Post Thickness Gauge Ruler 4cm