A pump set for use with a pumping apparatus having a rotor with a plurality of rollers mounted on the rotor rotatable about an axis of rotation is disclosed. The pump set comprises a cassette body comprising a stator member with a fixed portion secured to the cassette body, a second portion opposite the fixed portion, a reaction surface and a second surface opposite the reaction surface, the reaction surface defined between the fixed portion and the second portion, and a tube secured to the cassette body, at least a portion of the tube is disposed against the reaction surface.