The vacuum bag zipper is very easy to open and requires two hands to assist in opening. There is also an instruction manual inside, which is not a quality issue, but designed to prevent air leakage. Please be aware, thank you Product Name: Vacuum Compression Backpack Material: Waterproof Oxford cloth Size: 42*30*15CM After expansion: 42*30*20CM Capacity: can hold a 16-inch laptop Separate laptop bag Using the vacuum compression method: 1. Open the compressed vacuum lined bag 2, put the clothes on the air-tight zipper 3. Open the one-way exhaust valve 4. Press to exhaust the air inside Function: Breathable back Comfortable foam shoulder straps strap Anti-theft zipper pocket on the back Waterproof/wear-resistant/moistureproof Wet and dry separation area vacuum compression airtight password boarding Large capacity = 40L