This is Glo Amebo tariff plan that allows you to enjoy 5x bonuses on every recharge, and it also allows you to call all Nigerian networks.
If you are a Glo Amebo plan user, you can recharge N100 and get N500 worth of airtime to all any network of your choice.
You can even go up higher and higher, where you can easily recharge N200 and receive N1000 airtime bonus, while N1000 recharge gives you extra bonuses of N5000. Aside from Glo data bundle plan, they are very good for voice call.
The Glo Amebo plan is specially for those subscribers that makes a lot of calls, from business to families and even friends also.
If you are a user, you can simply recharge your line with *555*PIN#. And thankfully, it is available to all new and existing subscribers.