✔️1 3/4”long x 1”wide x 3/8”high ✔️【Compatible】CPAP air filters for any of your CPAP Machines from Philips Respironics M Series, PR System One Series and SleepEasy Machine. ✔️【Safe Material】Sterile sponge that does not fade & does not slag provides a better experience. ✔️【Simple operation】All we have to do is open the filter cotton port of the Philips ventilator and replace the filter that is no longer able to filter properly. ✔️【Customer service】If you have any questions, please feel free to contact us. Compatible: CPAP air filters for any of your CPAP Machines from Philips Respironics M Series, PR System One Series and SleepEasy Machine.