It is based on Windows 7.5 Mango operating system.
The specifications are as follows
Windows Phone 7.5 Mango OS
1 GHz processor
4 GB internal memory
4 inch Super AMOLED Screen
480 x 800 pixel Resolution
Skydrive storage (25 GB)
1500mAh battery
5MP Auto-Focus Camera with Flash
Front camera
Something apart from Android after long time by samsung, really a windows phone to look forward from samsung !