Back flatline icons set is a set that always grows...
Back Flatline Icons is now available both for personal and commercial usage under the royalty-free license.
Full preview and all information for the purchase of Back Flatline collection you can find here:
Green Flatback Set: http://www.shutterstock.com/sets/12179645-green-back-flatline.html?rid=3087110
Orange Flatback Set: http://www.shutterstock.com/sets/12321239-orange-back-flatline.html?rid=3087110