Artist painting canvas 100% Cotton, Cotton & linen mixed, 100% Linen Stretching ways: NSSB: Nails on Side & Staples on Back SS: Staples on Side NS: Nails on Side SB: Staples on Back SF: Staple free Thickness: 1.8cm ( 3/ 4â ) , 3.8cm ( 1-1/ 2â ) , 6.3cm ( 2.5â ) , 7.5cm ( 3â )