Surface Acoustic Wave Touch Screen technology:
Surface Acoustic Wave technology uses ultrasonic waves that pass over the touch screen panel. When the panel is touched, a portion of the wave is absorbed. This change in the ultrasonic waves registers the position of the touch event and sends this information to the controller for pr° Cessing. Because the panel is all glass there are no layers that can be worn, giving this technology the highest durability factor and also the highest clarity. This technology is recommended for public information kiosks, computer based training, or other high traffic indoor environments.

SAW touch screen specification:
Touch Type: Surface Acoustic Wave touch screen
Screen Sizes: 8"-29" Diagonal
Cable Interface: PC Serial/COM Port or USB Port
Touch Resolution:  4096 x 4096
Response Time: 10 ms. Maximum
Activation Force: 10-100 grams per square centimer
Positional Accuracy: 2mm maximum error
Light Transmission: 90 % -92%
Scratch Resistance: 3H pencil hardness
Life Expectancy: Over30 million
Temperature: Operating Temperature: -10º C ~+60º C
Storage Temperature: -20º C ~ +70º C
Choices of Glass Thickness: 0.7mm, 1.1mm, 2.0mm, 3.0mm, 5.5mm, Normal Glass, Chemically strengthened glass
Chemical Resistance: Alcohol, acetone, grease, and general household detergent
Software Drivers:  Windows XP / 2000 / NT / ME / 98 / 95, Linux, Mac OS

But Dimension only 8.4"touch screen, 10.4touch screen, 12.1touch screen, 14"touch screen, 15" touchscreen, 17" touch screen, 19" touch screen, 21" touch screen, 25"touch screen, 29" touch screen.
No small size.