Samsung launched there first phone of S line up with dual SIM and named as Samsung galaxy S duos, with 4 vivid display. This phone was a phone supporting HSPA+ network band with 4.0.4 android version with touchwiz interface.
Samsung through this device achieved ready to receive calls on either SIM when callis not already in progress, optionally it can receive two calls simultaneously. Camera was pretty great compared to other devices over that time with 5mp.Display size was 4 inch to make it handy.