When it comes to designing for mobile devices, nothing beats seeing your work on the device you made it for. But before any code is deployed, your best bet is to rely on the highest quality mockups you can find — They’ll let you take advantage of any given product, both its strengths and its weaknesses.

Designing within your constraints saves tons of time in the longrun, and clients (along with nearly everyone else) will certainly prefer a fully-polished look. Most importantly, as mobile devices like smartphones and tablets continue to grow in popularity, everyone from UI designers to web developers should be keeping these new screens in mind.

Here’s 13 Photoshop PSDs and Vectors for iOS, Android, and Nokia devices. Pick your favorite and put them to work!