This is a tool made of Japanese cypress wood, with a board thickness of about 15mm. It's a checking tool to see if items can be dropped off at Yu-Packet Post locations. It has a 4cm slit. When the board is thick, it's closer to the actual thickness of the post slot, reducing errors caused by angled insertion. It's also sturdy. You can check beforehand whether you can crush and push the package in. I created this item because I, as a Mercari user, thought it would be useful. I believe you will be satisfied with this product. I have been patronized by nearly 1,000 people so far. I have been able to create better products. Japanese cypress has a good fragrance and is very soothing. Wood is flexible, strong, and becomes more refined with use, and is environmentally friendly. Above all, the texture of the wood is the best. I have received many comments saying they were surprised by the durable and smooth feel of the product. I have also been using it for many years. I have included a photo on the 6th page to compare it with other thicknesses. It doesn't bend like a flimsy ruler made of thin material. It's as solid as an actual post slot. I don't think there are any commercially available posting measurement tools with this much thickness. To keep the price down, I also offer items with slightly thinner boards. Even the thinner ones have sufficient strength and accuracy. Please consider those if you want a cheaper option. The photos are for size and shape reference. The items shipped will be the same. If you want slits for measuring other thicknesses (1cm, 5cm, etc.), please contact me via the comments section of the order acceptance page. It may take some time, but I will try my best to meet your requests. I will use recycled packaging materials. If you purchase multiple items and they can be shipped together, I will reduce the price by the shipping cost. 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 #ThicknessGaugeMeasurementRuler #ThicknessMeasurementItem #ThicknessMeasurementGoods Yu-Packet Post Thickness Gauge Measurement Ruler 4cm Thickness Measurement Ruler Scale Yu-Packet Plus Measurement Ruler Mercari Shipping Mercari Scale Shipping Ruler Thickness Measurement Ruler Thickness Measurement Item Thickness Measurement Goods Thickness Measurement Scale