A closure system and various exemplary embodiments for devices including the closure system are disclosed. The closure system may include a base, a sideplate configured to rotate with respect to the base, and a retaining mechanism carried by the sideplate and configured to pivot with respect to the sideplate substantially transverse to an axis of rotation of the sideplate. The retaining mechanism may be configured to engage with a engagement protrusion of the base to prevent rotation of the sideplate. A chest roller, a snatch block, an ascender including the closure system and a method of use of the closure system, are additionally disclosed.