A covering for an architectural opening, said covering comprising: a rotatable roller defining an interior space; and a spring assembly received at least partially within the interior space of said roller , said spring assembly comprising: a non-rotatable member ; a first spring including a first end portion coupled to said non-rotatable member and a second end portion ; and a second spring including a first end portion and a second end portion , said first end portion of said second spring coupled to said second end portion of said first spring to rotate with said second end portion of said first spring , said second end portion of said second spring coupled to said roller to rotate with said roller ; a rotatable first housing ; and a second housing coupled to said roller such that said second housing rotates in unison with said roller ; characterised in that : said second end portion of said first spring is coupled to said first housing ; said first end portion of said second spring is coupled to said first housing ; and said second end portion of said second spring is coupled to said second housing . a rotatable roller defining an interior space; and a spring assembly received at least partially within the interior space of said roller , said spring assembly comprising: a non-rotatable member ; a first spring including a first end portion coupled to said non-rotatable member and a second end portion ; and a second spring including a first end portion and a second end portion , said first end portion of said second spring coupled to said second end portion of said first spring to rotate with said second end portion of said first spring , said second end portion of said second spring coupled to said roller to rotate with said roller ; a rotatable first housing ; and a second housing coupled to said roller such that said second housing rotates in unison with said roller ; characterised in that : said second end portion of said first spring is coupled to said first housing ; said first end portion of said second spring is coupled to said first housing ; and said second end portion of said second spring is coupled to said second housing . a non-rotatable member ; a first spring including a first end portion coupled to said non-rotatable member and a second end portion ; and a second spring including a first end portion and a second end portion , said first end portion of said second spring coupled to said second end portion of said first spring to rotate with said second end portion of said first spring , said second end portion of said second spring coupled to said roller to rotate with said roller ; a rotatable first housing ; and a second housing coupled to said roller such that said second housing rotates in unison with said roller ; characterised in that : said second end portion of said first spring is coupled to said first housing ; said first end portion of said second spring is coupled to said first housing ; and said second end portion of said second spring is coupled to said second housing . said second end portion of said first spring is coupled to said first housing ; said first end portion of said second spring is coupled to said first housing ; and said second end portion of said second spring is coupled to said second housing . <EOS>