The first number of the IP rating refers to protection against dust, while the second number refers to protection against liquid. E.g. a first number of 6 denotes that it is completely dustproof, and a second number of 7 denotes that the device can withstand full immersion in water.
The ATM rating indicates how much water pressure a device can withstand. 3 ATM is one of the lowest ratings and means that the device can only withstand splashes of water, whereas 20 ATM is one of the highest ratings and means that the device can be used for snorkeling and water sports.
The type of technology used in the display.
The device is dustproof and water-resistant. Water-resistant devices can resist the penetration of water, such as powerful water jets, but not being submerged into water.
Resistance to sweat makes it ideal for use while doing sports.
The bigger the screen size is, the better the user experience.
Pixel density is a measurement of a screen's resolution, expressed as the number of pixels per inch (PPI) on the screen. A higher pixel density translates into more clarity and sharpness for the images rendered on the screen, thus improving the quality of the viewing experience.
Damage-resistant glass (such as Corning Gorilla Glass or Asahi Dragontrail Glass) is thin, lightweight, and can withstand high levels of force.
Gorilla Glass is one of the most popular brands of chemically strengthened glass, manufactured by Corning. Several versions have been developed, the newer ones being more durable and providing better damage resistance.