It is save for battery use hmdx a115?

Hi, my parents gave me a present, the hmdx a115 ( http://trendgadget.net/search/iPhoneHMDXA115), I have the iPhone 4, I know there are some docks that when battery is charged, it continues charging, overcharging the iPhone battery.

Some knows if my iPhone 4 is safe with this charging dock?

It has two logos with the "Made for ipod" "Works with iPhone" http://www.flickr.com/photos/39875224@N06/5295618930/lightbox/

So many thanks in advance.

And sorry for my english, im not english.

Message was edited by: SamxFisher