Ultra-Durable A4 Sub Bag – Goodbye Paper Bags / Foldable

Built upon the same base model as the school bag proven to last over 3 years of daily use by junior high students — this sub bag is **incredibly durable**. It can be folded in half and stored inside a business briefcase. ▼ Examples of how customers use it (**Business Use**) ・Transporting case files for lawyers ・Carrying financial statements for tax accountants and CPAs ・Document bag for real estate appraisers ・Convenient for airport security checks ・Used with suitcases for business trips ・Laptop / tablet case ・Storage for golf cart transportation ・Company office / lunch carry bag ・For submitting government tender documents ・Document carrier at construction sites ・For carrying legal code books (**Personal Use**) ・Sheet music bag ・For theater performances ・For PTA or parent meetings ・For weddings or funerals ・For attending intensive English courses ・For carrying Bibles and hymn books ・For children’s cram school or extracurricular lessons (**Gift Use**) ・A present for a husband who still carries paper bags to work ・Father’s Day / Mother’s Day gift ・Bulk purchase for corporate anniversaries ▼ Size & Weight Unfolded: Width 280mm × Height 370mm × Depth 80mm Folded: Width 295mm × Height 205mm (equivalent to A4 size) Weight: 270g ▼ Capacity Approx. 8L ▼ Frequently Asked Questions **Q1: Can the bag stand on its own?** The gusset width is about 8cm, so it cannot stand by itself when empty, but will stand if you place a water bottle or tumbler inside. **Q2: Can it be worn on the shoulder?** The handle length is intentionally designed for hand-carry only, because: ・For shorter users, it may touch the ground. ・Longer handles tend to swing like a pendulum. Children (up to elementary school age) can shoulder-carry it comfortably. **Q3: Is it waterproof in heavy rain?** It can withstand light splashes or brief showers, but under prolonged rainfall, water may seep in through the seams — so please avoid overexposure. **Q4: Is there a horizontal (landscape) version?** Although many have asked, a wider shape can become inconvenient on crowded trains such as the Yamanote Line, so it is not currently available. **Q5: Does it include a bottom board?** Yes, it does. The board helps the bag stand upright and stable when carrying heavy items. **Q6: Is there an inner pocket?** For smoother access, the pocket is placed outside rather than inside. It fits a smartphone or planner perfectly.