WD Musical Instrument Collection - Portable/Back Backpack 背 The strap can be cut to the right length 材质 Material: cotton Size: about 37x40 cm Cleaning method: It is recommended to wash by hand to avoid vigorous washing. ⚠️ Precautions 1. This series of products will be shipped about 3-7 days after the order is placed. If you need it urgently, please confirm the shipping time with us! 2. This product is a custom-made product. If there is no major defect after the sale, there is no replacement service!