hi, I thought dacron but some else said fast flight, is there much difference? I thought fast flight lacked the slight give needed for elbs, but he said not...It's likely that it's Dacron or something similar since that's recommended for traditional bows without reinforced limb tips in the 12-16 strand range. Could be either B50 or B55 or something else but it's unlikely to make a large difference.
the string on my 50# boo backed bow has a much thinner string, due to what you said I gues that must be fast flight and my osage bow must be dacronA 14 strand fastflight would be pretty thin as the norm is nearer 18. Dacron is often white while fastflight is often black or some strong colour.