Is that the Goblin 700 that you are looking for batteries for?
Most people fly them on two x 6S 5000mAh. They are seperate batteries that you wire up in series, so that results in 12S 5000mAh. (when you wire in series voltage (cell count) increases but mAh stays the same). The Goblin 700 will of course fly with a range of batteries from about 4500mAh but personally I'd not go above 5000mAh due to weight. 3300mAh batteries aren't big enough for the 700, you could fly on them if you really wanted but you would be very tail heavy and have very short flight time.
14S is also an option but in that case you reduce mAh to keep weight down (two x 7S of about 4400mAh), but unless you are the hardest of hardcore 3D flyers you wouldn't notice the difference. For 14S you also need a low Kv 14S motor. You also need a charger that will do 7S.
You can get ready assembled 12S 'stick packs' but almost everyone simply uses two seperate 6S batteries. The stick packs are as you point out just two 6S batteries with a shrink cover pre applied.
For what it's worth the same batteries (6S 5000mAh) will work fine in the Goblin 770 too, that's exactly what i use in mine. The 770 is virtually the same weight as the 700 so doesnt need any more power.
