Select Multiple Product Options/Attributes?

[CustomGaming]

Ok this is basically what i am looking for, i have a website (obviously) 'www.CustomGaming.com.au' and in the product info pages, i have options as images contribution installed.

 

But here is the issue i am going to be introducing a new option for Additional Mods, in which there will be 4 attributes/options, so it would be built like this,

 

Additional Mods:

 

*Mod1

 

*Mod2

 

*Mod3

 

*Mod4

 

Now for these options i want to be able to select more than one of them is that possible or can anyone give me a hand?