Glo campus booster doubles your data for you on every recharge,i.e if you had already subscribed for the data and did not exhaust it but subscribe again for the data you may get 350mb depending on your usage.
HOW TO SUBSCRIBE + Data Volume
Diall *777# to activate then choose any of the plans you wish to activate.
HOW TO CHECK DATA BALANCE
Dial *127*0# or by visiting www.hsi.go.com or dial *777# for data balance inquiry.
SOURCE: GLO NIGERIA