Philips Respironics EverFlo Whisper Cap Kit

You can click this sound absorbing whisper cap kit onto the grille at the back of the Philips EverFlo oxygen concentrator. In some countries the cap is standard on the concentrator, in other countries it's an optional accessory. There is foam on the inside of the cap, which somewhat reduces the sound of the concentrator. It's recommended to check the foam regularly. If the quality of the foam deteriorates, the cap will need to be replaced.