b'ALERTS & FAULTS TheNP SIMS is a silent system and has no audible alarms but does exhibit two visible indicators for the delivery of negative pressure.1.The dressing constricts to the absorbent dressing pad giving the entire absorbent dressing a taut appearance and firmness to touch. In addition, the contour of the incision may be visible.2.The blue sealing flap on top of vacuum chamber is slightly depressed in the vacuum chamber activation slot.NP SIMS Health Care Practitioner Instructions for Use (IFU)15'