Responsive Design Testing Tool
Screenqueries allows you to easily check your website on a range of device screen sizes from smartphones, tablets and beyond.
Use the preset screen sizes for popular smartphones and tablets including iPhone, iPad, Samsung SII, Nexus 4, etc.
There is also a handy rotate button to view the website in landscape orientation for the device chosen.
Excellent tool for quickly testing your responsive website across a number of different screen sizes.
Screenqueries is free.