Capsule and plug for a concentrated refill capsule

A plug for use in a cap assembly of a refill capsule, the plug comprising

• a tubular body with an open proximal end and an open distal end, wherein the open proximal end is surrounded by a first rim, and wherein the first rim further comprises at least fin and second projections extending in a proximal direction from the first rim,
• wherein a proximal surface of the projections provides a proximal-facing abutment surface for bearing against a bearing surface of a frangible sealing component of a cap assembly;
• wherein the proximal-facing abutment surface extends in a plane that is orthogonal to a longitudinal axis (A) of the tubular body;
• a skirt extending around the tubular body, and comprising a tubular skirt wall arranged coaxially with respect to the tubular body, the skirt wall being spaced apart from the tubular body in a radial direction to form a plug recess between the skirt wall and the tubular body, wherein the plug further comprises an outwardly extending flange comprising a distal-facing abutment surface for abutting a rim of a refillable vessel, and
• wherein the proximal-facing abutment surface has at least two fold rotational symmetry with respect to the longitudinal axis (A).