Nasal seal for a respiratory patient interface

A nasal seal for a respiratory therapy mask for contacting the face of a user, the nasal seal comprising:

• a main body defining a cavity and a fluid inlet;
• two nasal prongs projecting from the main body for the delivery of fluid to the user's nares;
• and
• a transition fillet around a base of each prong, the transition fillet defining a transition between the main body and the base of each prong, the transition fillet extending in a radially outward direction from the base of each prong between a first edge of the transition fillet at the nasal prong and a second edge of the transition fillet at the main body, the second edge positioned radially outward from the first edge, an outer surface of the transition fillet defining a concave surface in the radial outward direction extending from the first edge and the second edge;
• wherein the transition fillet has a chord length from the first edge to the second edge, wherein the chord length of each transition fillet is constant around the base of each prong.