Like some of the other lines and sizes in the famous brand, the Byron Londineses Siglo XX Ecuadorian Robusto Grande (5 1/2" x 54) is comprised of a blend that is not disclosed. The origin of the filler, wrapper and binder are unknown to those outside of the company. What we do know is that the secret blend delivers a medium to full body punch that is undeniably complex and full of flavor.