Sorry to be Captain Obvious here, but if you aren't sure you know what you are asking for, should you really be posting in the first place, or might you be better off maybe reading up in the Big Book of Amiga Hardware (easily Googled) first?
As above; i didnt know i wasnt sure. i thought i was sure, but yes i get your point, in future before i post requests ill google it to have a look at all the available types of hardware / software. makes sense.
The BBoAH (http://www.amiga-hardware.com/) is a fantastic resource and the pictures are brilliant for showing what you should be looking for. Let it not be said that we aren't here to help as well as educate