They are classified with different IP-classes.
Xperia Go:
This product is rated IP67 according to the International Protection classification system. IP67 indicates that when the phone is correctly mounted to maintain its dust and water resistant qualities, there is no ingress of dust (digit 6) and that ingress of water (digit 7) in harmful quantity shall not be possible if the device is dropped in fresh water under up to 1 meter of submersion for a duration of maximum 30 minutes.
Xperia Acro S:
This product is rated IP55 / IP57 according to the International Protection classification system. The first digit in the IP rating (5) indicates that the device is protected against dust. The second digit indicates how well the device is sealed against entry of moisture or liquid. IPX5 indicates that the phone continues to function when directly subjected to 12.5 L of water per minute from all directions using a 6.3 mm inside diameter nozzle at a pressure of 30 kN/m² and a distance of approximately 3m for at least 3 minutes . IPX7 indicates that the phone continues to function and that no water gets inside when the device is dropped in fresh water under up to 1 meter of submersion for a duration of maximum 30 minutes.
Xperia Z:
In compliance with IP5/7 and IP5X, Xperia Z is protected against the ingress of dust and is water resistant. Provided that all ports and covers are firmly closed, the phone is (i )protected against low pressure jets of water from all practicable directions in compliance with IP 55; and/or (ii) can be kept under 1 metre of freshwater for up to 30 minutes in compliance with IP 57. The phone is not designed to float or work submerged underwater outside the IP55 or IP57 classification range and should not be exposed to any liquid chemicals. If liquid detection is triggered on the handset or battery, your warranty will be void.
Xperia ZL is not water resistant.
