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.