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 in your package. I created this item because I, as a Mercari user, thought it would be useful. I believe you will be completely satisfied with this product. I have been patronized by nearly 1,000 people so far. I have been able to create even better products. Japanese cypress has a pleasant aroma and is very soothing. Wood is flexible, strong, and becomes more refined with use, making it environmentally friendly. Above all, the texture of the wood is superb. I have received many comments saying they were surprised by how durable and pleasant to the touch it is. 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 and flex like a thin ruler. 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 are strong and accurate. Please consider those if you prefer a more affordable option. The photos are for size and shape reference. The items shipped will be the same. If you would like a slit 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 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 price by the shipping cost. I may change between Yu-Yu Mercari and Raku-Raku Mercari shipping services without notice. Thank you for your understanding. #TakawataHandmade #TakawataPackingScale #YuPacketPost4cm #YuPacketPost #ThicknessMeasurementRuler #ThicknessGauge #ThicknessMeasurementItem #ThicknessMeasurementGoods Yu-Packet Post Thickness Gauge 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