04/15/2013 09:24 am ET Updated Jun 15, 2013

Elle and Blair on the Best and Worst of Spring 2013 Fashion (WATCH)

Beauty and fashion gurus Elle and Blair Fowler stop by the What's Trending to chat about the hottest seasonal trends, how to pick the perfect phone case for your outfit, and what's in store for 2013.

Along with their successful YouTube channels, makeup line, Beneath The Glitter novel, and accessory line with, the sisters also launched their own line of stylish phone cases at

"We developed this line thinking you change your bag and your shoes out for your outfit, but your phone is always in your hand, so why wouldn't you go head and change that out, too?" Blair asks.

"We launch them to go with the fashion season," Elle adds.

Adding to that, Elle and Blair have designed shoes and handbags, so possibly a full fashion line could be coming up in the future.

As girl talk gets rolling in the studio while critiquing a "Swaggy" Justin Bieber case, the girls chime in to reveal their feelings towards the Biebs.

"Justin Bieber does have swag. No matter what you want to way, think about the way he dances," Blair says. "We've seen him perform live at the Teen Choice Awards and he really... he has a presence. He has swag."

So, if Justin has his Swag Army, shouldn't the Fowler sisters have their own army of fans? What do you think their legion of viewers should be called?

Finally, we ask Elle and Blair to give their opinions on some crazy Fashion Week runway looks and trends, featuring designs from Betsey Johnson, Jeremy Scott, Eckhaus Latta and The Blonds.

Check out their website for more fashion tips and look out for their second book coming out the fall!

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