 A yarn's usefulness for a knitting project is judged by several factors, such as its "loft" (its ability to trap air), its "resilience" (elasticity under tension), its washability and colorfastness, its "hand" (its feel, particularly softness vs. scratchiness), its durability against abrasion, its resistance to pilling, its "hairiness" (fuzziness), its tendency to twist or untwist, its overall weight and drape, its blocking and felting qualities, its comfort (breathability, moisture absorption, wicking properties) and of course its look, which includes its color, sheen, smoothness and ornamental features.Other factors include allergenicity; speed of drying; resistance to chemicals, moths, and mildew; melting point and flammability; retention of static electricity; and the propensity to become stained and to accept dyes.Different factors may be more significant than others for different knitting projects, so there is no one "best" yarn.