Xitan Microbore elastic offers major advantages over conventional hollow elastic. A smaller centre tube means that Xitan Microbore is around 30% thinner and lighter than the equivalent standard hollow, but retains the same 7x stretch factor. Microbore also runs much smoother under load as it resists flattening at the bush under pressure. In test it also lasted longer. The smaller sizes are the perfect silverfish and F1 elastics.