These Vacurama Premium central vacuum bags are compatible with OVO and Nadair central vacuum systems. They fit the models: OVO-700ST-25H, OVO-630ST-25H, OVO-630ST-18B, OVO-550ST-18B and Nadair 600AL-18, Nadair 700AL-18, Nadair 600AL-22, Nadair 700AL-22, Nadair FD-12.5L-3NAD. Made with sturdy and tear-resistant non-woven cloth material, these bags make a perfect and economical replacement for your CV system. (The OVO, Nadair and other brand names and logos are the registered trademarks of their respective owners. Any use of the OVO, Nadair or other brand names or model designations in describing this product is made solely for purposes of demonstrating compatibility.)