Responsive Viewer - View multiple screen dimensions in one view
FitSW - App for personal trainers. FitSW personal training software helps fitness coaches easily build workout & meal plans, track client progress, & more on any device.
Responsinator - Designed to test responsive websites on different devices.
My PT Hub - The World's #1 Software For Personal Trainers.
Responsive Website Test - Test any website on desktop, mobile, and tablet
Everfit - A platform for personal trainers to train clients online