Abstract: The present invention is directed to: a non-interlacing expirating yarn bulker comprising a body having an enclosed yarn passage extending therethrough. The yarn passage includes an inlet region, a throat region and an expanding region. A single pressurized fluid channel extends through the body and intersects with the yarn passage in the throat region. Cross sectional areas at certain defined locations in the yarn passage exhibit predetermined relationships. In addition, the inlet region and the pressurized fluid channel both are symmetrical about a common reference plane of symmetry;a replaceable wear member insertable into a body of a jet having a yarn passage with an inlet region and a throat region. The wear member has an upstream face, a downstream face, and a channel extending therebetween. The intersection of the channel and the downstream face of the member defines a wear edge.