, ▁the ▁NFL ▁generates ▁$ 1 . 2 ▁billion ▁ann ually ▁in ▁j er sey ▁sales , ▁with ▁the ▁NBA ▁second ▁s elling ▁$ 9 0 0 ▁million ▁ann ually . ▁Another ▁use ▁of ▁the ▁alternate ▁uniform ▁is ▁for ▁ident ifying ▁with ▁causes , ▁like ▁the ▁Central ▁Coast ▁Mar in ers ▁wear ▁an ▁alternate ▁p ink ▁k it ▁on ▁p ink ▁rib bon ▁day . ▁ ▁Ext ra ▁alternate ▁uniform s ▁or ▁fourth / fif th ▁k its ▁are ▁not ▁commonly ▁used , ▁but ▁are ▁sometimes ▁required ▁when ▁teams ' ▁other ▁uniform s ▁cause ▁color ▁cl ash es , ▁or ▁the ▁uniform s ▁are ▁un available ▁to ▁use . ▁In ▁cases ▁where ▁teams ▁have ▁worn ▁more ▁than ▁three ▁k its ▁in ▁the ▁same ▁season , ▁the ▁extra ▁k its ▁were ▁usually ▁rec yc led ▁from ▁previous ▁seasons . ▁ ▁Third - choice ▁j er se ys ▁or ▁uniform s ▁are ▁used ▁in ▁all ▁four ▁Major ▁professional ▁sports ▁le agues ▁in ▁the ▁United ▁States ▁sports ▁le agues . ▁ ▁Third ▁k its ▁are ▁common place ▁in ▁professional ▁European ▁association ▁football ▁and ▁in ▁some ▁professional ▁European ▁rugby ▁union ▁clubs . ▁Altern ate ▁j er se ys ▁are ▁common ▁in ▁Australia ' s ▁two ▁biggest ▁domestic ▁le agues , ▁the ▁Australian ▁Football ▁League ▁( A uss ie ▁rules ) ▁and ▁National ▁Rugby ▁League ▁( rug by ▁league ). ▁ ▁Background ▁For ▁home ▁and ▁away ▁j er se ys ▁in ▁North ▁America , ▁historical ▁convention ▁has ▁often ▁dict ated ▁the ▁colors ▁used ▁by ▁teams ▁in ▁a ▁given