Mod8 increases the default amount of time that you can ban for by 2 hours on chats that you are a moderator. By default, moderators can ban for a maximum of 6 hours. In this case, acquiring Mod8 will allow you to ban for 8 hours.
GControl allows the ability to change the amount of time moderators can ban for. If you own Mod8, you are able to ban for an additional 2 hours. Mod8 does not affect owners.
Note: Mod8 does not stack, meaning that buying multiple powers will not extend the maximum time a moderator can ban. However, it will stack with one GControl power. If you have both Mod8 and GControl, you can ban for up to 4 hours longer than what the default is set to.