▁har v ested ▁from ▁which ▁must ▁be ▁taken ▁into ▁account ▁when ▁considering ▁the ▁uses ▁of ▁a ▁finished ▁kn itting ▁object . ▁Example : ▁W ool ▁is ▁well ▁su ited ▁to ▁items ▁which ▁will ▁be ▁used ▁to ▁hold ▁in ▁heat , ▁even ▁when ▁d amp , ▁such ▁as ▁winter ▁h ats ▁and ▁mitt ens . ▁Lin en , ▁however , ▁would ▁be ▁well ▁su ited ▁to ▁a ▁light ▁summer ▁swe ater ▁when ▁breath ▁ability ▁is ▁a ▁factor . ▁ ▁Syn th etic ▁fib ers ▁are ▁made ▁by ▁forcing ▁a ▁thick ▁solution ▁of ▁polym er ized ▁chemical s ▁through ▁sp inner et ▁no zz les ▁and ▁hard ening ▁the ▁resulting ▁fil ament ▁in ▁a ▁chemical ▁bath . ▁Natural ▁fib ers ▁are ▁generally ▁so fter ▁and ▁more ▁comfortable ▁whereas ▁synth et ics ▁are ▁dur able ▁and ▁easier ▁to ▁d ye . ▁Some ▁fib ers ▁can ▁be ▁harder ▁to ▁kn it ▁with ▁than ▁others ▁for ▁a ▁variety ▁of ▁reasons . ▁Cot ton , ▁for ▁example , ▁doesn ’ t ▁stretch ▁as ▁much ▁as ▁w ool , ▁and ▁as ▁such ▁requires ▁the ▁kn itter ▁to ▁work ▁harder ▁to ▁maintain ▁gauge . ▁ ▁Before ▁kn itting , ▁the ▁kn itter ▁will ▁typically ▁transform ▁a ▁h ank ▁into ▁a ▁ball ▁where ▁the ▁y arn ▁emer ges ▁from ▁the ▁center ▁of ▁the ▁ball ; ▁this ▁making ▁the ▁kn itting ▁easier ▁by ▁prevent ing ▁the ▁y arn ▁from ▁becoming ▁easily ▁tang led . ▁This ▁transformation ▁may ▁be ▁done ▁by ▁hand , ▁or ▁with ▁a ▁device ▁known ▁as ▁a ▁ball w inder .