1. Easy Installation: Replacement filter cartridge is a part of breathing machine, which is easy to install, does not need any special tool. 2. Portable Size: Oxygen concentrator filter is small in size and light in weight, which is easy to carry in your bag for convenient use. 3. Smoothing Edges: Oxygen concentrator filter adopted fine workmanship, with excellent details and rounded edges, will not scratch your hands. 4. Excellent ABS: Oxygen concentrator filter box made of ABS material, firm and sturdy, which are not easy to be . 5. Regular Replacement: Breathing machine cartridge filter should be replaced regularly to keep the machine in a good working condition. Item Type:Oxygen Concentrator Filter Colour:As Shown Material:Plastic Package Contents: 4 x Repalcement Filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.