Are the portable chargers reliable?

I use my phone in all of my classes to listen to music every day and I'm sick of using the outlets in the classrooms to charge my phone. I found this charger on the Best Buy website http://www.bestbuy.com/...Id=9194103 is it reliable? Plus, my school has bomb threats once in a while so thats a reason why I need one. I have a bunch of Best Buy gift cards. I have a iPod Touch 5 Gen (I use for games) iPhone 4S I use as a normal phone (and music too). I'm fifteen, a guy. Would that charger be reliable? Please let me know, thanks

I have that same charger. I've had it for about 9 months now and have no problems with it. It lasts a while and has enough juice for at least a full charge.

The facts of life on parts made for the electrical and electronics markets. MASS production reduces costs however the compromise is the quaLITY SUFFERS.
SO power supplies do not last as long.