The most common material for waterproof bags is PVC tarpaulin. And for good reason. PVC tarpaulin has a number of properties that makes it ideal for use in waterproof bags. These characteristics include being water impermeable, stain resistant, anti-static, UV protection, antibacterial and mildew resistance, extreme temperature resistance, pliable and high tear strength.

Let's look at each in turn, examining why each characteristic is important for its use in watertight bags:

• Water impermeable: Well obviously, being water impermeable is the number one criteria for PVC tarpaulin's use in watertight dry bags. I don't think much more explanation is required on this one.

• Stain resistant: The stain resistance of PVC tarpaulin means it is easy to clean, keeping your dry bag looking newer for longer.

• Anti-static: väska There's nothing worse than when you have a dry bag over your shoulder and as it rubs on your bag it creates static and clings to your clothes. It gets very annoying. The anti-static properties of PVC tarpaulin ensure this does not happen when you have one of these bags over your shoulder.

• UV protection: Waterproof dry bags spent a lot of time outside in the sun. As a result, they need to be resistant to the sun's harmful UV rays to ensure the bag doesn't melt, warp or fade. This characteristic is essential to provide your waterproof bag with a long life.

• Anti-bacterial and mildew resistance: Especially important when you use your watertight bag to stop wet things getting dry things wet. When your dry bag is sealed with wet clothes or towels inside, the potential for mould or bacteria to grow is high. That's why you need the anti-bacterial and mildew resistant properties of PVC tarpaulin - it stops nasty things growing inside your waterproof bag.

• Extreme temperature resistance: Similar to the reasons UV protection is important, waterproof bags can spend a lot of time in the sun, or conversely in the cold. The dramatic range of temperatures dry bags can be exposed to means the material they're made of needs to be able to withstand dramatic hots and colds.

• Pliable: Importantly, the material for waterproof bags must be pliable. It must be able to be easily folded over to create the seal. Similarly, it must also be able to move to accept odd shaped contents, and of course, sit comfortably on your back. If it wasn't pliable, it would be an uncomfortable bag. The pliability of PVC tarpaulin makes it an ideal material for use in watertight bags.