MAIN BEAM/FRAME FOR SPORT RIDER 2 (Z-SPEC) Comes stock on the Z-Spec Sport Rider 2 (HR1000-Z) and the Z-Spec Sport Rider 2 for Recumbent Bikes (HR1000Z-R) Includes black end cap This main beam uses the square ratchet vertical post . If you need the previous version that used the round Precision Slide vertical post , click here: MB1000-Y Please note a round vertical post will not secure in place with this main beam