Abstract: A torsion spring adjuster for a rolling shutter is provided. A support plate has a first flange with a hole. A wheel is rotatably mountable on the support plate. The wheel has: a drive recess shaped to engage an end of a torsion spring; a first set of recesses around a circumference of the wheel, the first set of recesses being a first lateral distance from a first end of the wheel; a second set of recesses around a circumference of the wheel, the second set of recesses being a second lateral distance from the first end of the wheel. When the wheel is mounted on the support plate the first lateral distance aligns the first set of recesses with the hole of the first flange of the support plate, and the second lateral distance aligns the second set of recess past the first flange of the support plate.

Abstract: A main slat for a roller shutter system is provided. The slat includes a slat body having a first and second end, a hook end connected to the first end of the slat body, a screw boss connected to the second end of the slat body, and a receiving end connected to the screw boss. The hook end and the receiving end are each shaped such that the hook end is laterally insertable into the receiving end of an adjacent main slat and when so inserted forms a hinge. The slat body has a central cross section including at least first and second portions, the first and second portions each having a different radius of curvature.