Reversible vacuum pump conveys complex shapes, bulk materials, and small parts up to 4 in. If clog occurs, operator manually presses button on pump momentarily reversing airflow to dislodge blockage. Releasing button returns airflow to original direction. Vacuum flow rate is regulated by input pressure and ranges from 0-375 scfm. Sixteen models range from 1/8-4 in. ID with vacuum levels from 0-10 in. Hg.