I have just started what I hope will become a reference list of existing ultralight amps and cabs, since there has been so much interest in them. Reference thread: http://www.talkbass.com/forum/showthread.php?p=2598099 As I started to list them however, I realised that in order to define the scope of what should be on the list, we need some kind of definition for ultralight. What would be the best way to define ultralight? For amps: anything under 10lbs? 20lbs? 30lbs? For cabs: anything under 30lbs? 40lbs? 50lbs? Or should the maximum weight definition depend on the type of cab, speaker configuration? If so, what should they be? What about combos?