C.F. Martin Acoustic Guitar 12 String Phosphor Bronze Extra Light, .010 - .047, MSP-4600star rating 5Donald MostromNovember 20, 2009I use these strings exclusively on the small-bodied (00 size) 12-string guitars I build. I find they provide plenty of punch, clean clear notes and a remarkably full sound. I've found that larger (even jumbo) 12 strings can't begin to match the power of my 00 12-string guitars fitted with these strings.