Waterproof backpack for swimming. Is IPX6,IPX7,IPX8,IPX9 waterproof ?

I would like to buy a backpack for swimming, that should protect my stuff from sea water. I found multiple types of backpacks with different water resistance standards. Is IPX6, IPX7, IPX8 or IPX9 waterproof ?

It may be a bit difficult to buy a backpack that is really waterproof and suitable for swimming.

Please mind the difference between water-resistant items and water-proof items. Water-resistance is ability to resist the penetration of water partially, but not entirely.

• IPX6 means that item is water resistant. This standard protects against water stream, but not against water immersion or submersion.
• IPX7 standard protects against water immersion up to 1 meter of water for up to 30 minutes. But still, it does not protect against water submersion.
• IPX8 standard protects against water submersion. Items can resist a low pressure, so they can't be submerged too deep.
• IPX9 standard protects against water submersion and even against higher pressure.

I would say that IPX8 or IPX9 backpack should cover your needs and protect your stuff when swimming on the water (not under water). After you buy a waterproof backpack, first, I recommend to put some non-expensive stuff inside to test it.