I have been using this for some time now.
When ever i subscribe for 1.5gb for 1000 Naira, i will get 3gb!
HOW IT WORK'S
1. Tweak this imei 356602075735**
2. After tweaking ur imei, kindly put ur phone on Airplane Mood.
3. Remove it and wait for your confirmation message.
4. When u get the message 4rm MTN, Then
Subscribe to any data of ur choice.
5. When u subscribe then check ur data with
*1314#
You will see that ur data is calculated times 2.
GOODLUCK
NB: IT LAST FOR 6MONTHS
ENJOY