OS Details

Asus Zenwatch 2 has been launched in September 2015.
Asus Zenwatch 2 have

Screen Dimensions

Asus Zenwatch 2 screen size is 1.63 inch with ~ 42.5% body ratio of actual device size. Physical dimensions for Asus Zenwatch 2 device is 1.95 x 1.60 x 0.43 INCH or ( 49.6 x 40.7 x 10.9 MM).

Displaying of Units are in this order "Height x Width x Thickness"

Screen Pixel Density and CSS Pixel Ratio

"Pixel" is smallest unit/element of any display.

The total number of pixels that fit into an inch is referred to as "Screen Density" or "Pixel Density" and it measured as "Pixels Per Inch".
Pixel Desnsity have limits to display Pixels Per Inch depends on different screen sizes. When number of pixels per inch increases than it's screen-size limit, the Display resolution will increase but actual device width/height in pixels remain same. Actual device pixels are known as Device Independent Pixels or CSS Pixel Ratio.

Asus Zenwatch 2 resolution is 320 x 320 ^PX with ~ 278 pixel desnsity.
Asus Zenwatch 2 viewport size is 213 x 213 ^PX with ~ 185 actual pixel density, which means it have 1.5 hdpi display pixel density.

Screen Resolution and Viewport

The sum of pixels which are displaying on a device is called as "Screen Resolution". and sum of actual pixels of any device is reffered to as "Viewport".

Asus Zenwatch 2 have 1.63" physical screen size and its resolution is about 320 x 320 Pixels with approximately 278 PPI pixel density. Asus Zenwatch 2 has viewport size 213 x 213 Pixels and its pixel ratio is about 2.

For better understanding screen actual sizes, viewport sizes, display resolution and about their density click here.

CSS Media Queries

Asus Zenwatch 2 Media Queries

@media only screen and (min-width: 213px) and (max-width: 319px) { /* Your Styles... */ }

Asus Zenwatch 2 Min-Width Media Queries

@media only screen and (min-width: 213px) { /* Your Styles... */ }

Asus Zenwatch 2 Min-Height Media Queries

@media only screen and (min-height: 213px) { /* Your Styles... */ }

Asus Zenwatch 2 Min-Width Media Queries

@media only screen and (max-width: 213px) { /* Your Styles... */ }

General Media Queries for Smart Watches

@media only screen and (max-width: 319px) { /* Your Styles... */ }

In current era smart watches have no viewport size greater than 319px. So 319px is choose as max-width, also it will not disturb your styles for any kind of mobiles.

Retina 2x Media Query for Smart Watches

@media
  only screen and (-webkit-min-device-pixel-ratio: 2),
  only screen and (   min--moz-device-pixel-ratio: 2),
  only screen and (     -o-min-device-pixel-ratio: 2/1),
  only screen and (        min-device-pixel-ratio: 2),
  only screen and (                min-resolution: 192dpi),
  only screen and (                min-resolution: 2dppx) { 
    /* Retina styles here */
}
                                

Asus Zenwatch 2 Specifications

• Launch Date September 2015
• Physical Screen Size 1.63 INCH
• Resolution 320 x 320 PX
• Viewport Size 213 x 213 PX
• Pixel Density 278 PPI
• Device-Independent Pixels 185 PPI
• Pixel Ratio 1.5 hdpi
• Width 320 PX
• Height 320 PX
• Device Width 213 PX
• Device Height 213 PX
• Dimensions 49.6 x 40.7 x 10.9 mm (1.95 x 1.60 x 0.43 in)
• Weight g - oz