 They sprayed 15 Pholcidae spiders with water containing the nanotubes or flakes.The resulting silk had a fracture strength up to 5.4 GPa, a Young’s modulus up to 47.8 GPa and a toughness modulus up to 2.1 GPa, surpassing both synthetic polymeric high performance fibres (e.g.Kevlar49) and knotted fibers.