IPX7 Water Certified - Professional level waterproof rating. The case will remain waterproof to a depth of 1 meter for at least 30 minutes. Full splashdown accepted captain. If you drop your device in water up to 3 feet (1 meter) your device is still going to work.
IPX6 Water Certified - Shockproof IPX6 rated dust and waterproof toughness that lets you ride through storms, over mountains and down the trail. Protects from powerful water jets. So if you modified your super soaker with an air compressor and an aftermarket tip, your stuff is still safe.