An adjustable socket system comprising: a base; a plurality of longitudinal supports connected to the base and extending along a longitudinal axis of the adjustable socket system; a plurality of shell components operatively connected to the plurality of longitudinal supports and at least in part defining a receiving volume adapted to receive a residual limb, the adjustable socket system movable between an open configuration in which at least some of the plurality of shell components are moved radially outward relative to the longitudinal axis to loosen a fit of the adjustable socket system, and a closed configuration in which at least some of the plurality of shell components are moved radially inward relative to the open configuration to secure the fit of the adjustable socket system on the residual limb; and a tightening system arranged to selectively move the adjustable socket system between the open and closed configurations, the tightening system including: a tensioning unit including at least one movable connection point and a handle defining a moment arm rotatable about a rotation axis; and at least one tensioning element operatively coupled to the handle via the at least one movable connection point and to at least one of the plurality of shell components via at least one control point, wherein rotation of the handle about the rotation axis from an off position to an on position displaces both of the at least one movable connection point and the at least one tensioning element relative to the at least one control point to tension the at least one tensioning element and to move the adjustable socket system to the closed configuration; characterized in that the handle has a binary configuration such that the handle is only positionable in the on position and/or the off position. a base; a plurality of longitudinal supports connected to the base and extending along a longitudinal axis of the adjustable socket system; a plurality of shell components operatively connected to the plurality of longitudinal supports and at least in part defining a receiving volume adapted to receive a residual limb, the adjustable socket system movable between an open configuration in which at least some of the plurality of shell components are moved radially outward relative to the longitudinal axis to loosen a fit of the adjustable socket system, and a closed configuration in which at least some of the plurality of shell components are moved radially inward relative to the open configuration to secure the fit of the adjustable socket system on the residual limb; and a tightening system arranged to selectively move the adjustable socket system between the open and closed configurations, the tightening system including: a tensioning unit including at least one movable connection point and a handle defining a moment arm rotatable about a rotation axis; and at least one tensioning element operatively coupled to the handle via the at least one movable connection point and to at least one of the plurality of shell components via at least one control point, wherein rotation of the handle about the rotation axis from an off position to an on position displaces both of the at least one movable connection point and the at least one tensioning element relative to the at least one control point to tension the at least one tensioning element and to move the adjustable socket system to the closed configuration; a tensioning unit including at least one movable connection point and a handle defining a moment arm rotatable about a rotation axis; and at least one tensioning element operatively coupled to the handle via the at least one movable connection point and to at least one of the plurality of shell components via at least one control point, wherein rotation of the handle about the rotation axis from an off position to an on position displaces both of the at least one movable connection point and the at least one tensioning element relative to the at least one control point to tension the at least one tensioning element and to move the adjustable socket system to the closed configuration; characterized in that the handle has a binary configuration such that the handle is only positionable in the on position and/or the off position.