Zee News Why do Pen caps have a tiny hole at the top? The hidden reason will leave you shocked April 17, 2026 easyway The hole in pen caps balances air pressure. When you close a pen, the cap traps air inside. Without a vent, pressure differences could make the cap hard to remove or even cause ink leakage. from Zee News :India National https://ift.tt/AiCHOnF