Zong Data SIM are packed with Zong Mobile Broadband devices like zong 4G wingle, super 3G dongle or zong 4G wifi. The internet packages on zong data SIM are different from normal SIM and in data SIM the number of GBs are more in competitive prices.
In start zong were not issuing Data SIM alone, and for that you must have to purchase any zong internet device. But now zong are issuing data SIM and you can get it from any franchise or service center. But if you buy it alone than double GBs offer will not be effective on that. The other way to buy it, search it on internet and you find many of users are selling these Data SIM alone without any wingle or other device. Because they buy it with wingle or any other device and selling it after unlocking. Make sure before buying that SIM is not registered and it is zong MBB SIM.
After that you can register it through biometric verification and for first time package activation you need to visit franchise and map it with your master number. Master number can be any other zong number from where you can control your zong MBB SIM.
Update: Now Zong separately launched their Internet only SIM and it is available on Zong service centers, Franchise and Retailers. You can get it and after biometric verification, the SIM will be ready for use on any device.
The Packages on Zong data or Internet SIM are different as compared to normal SIM. You have to subscribe any Zong MBB bundle on your Internet SIM to use it.