By choosing Eheim, you won’t go wrong. Because you have chosen a reliable, millionfold tried and tested piece of equipment. All models perform to the highest quality standards. First class components and carefully matched features ensure perfect performance. You will be very satisfied. 
Eheim O Ring / Sealing Ring for external Canister filter head for 2211 / 2213 / 2215 & 2217
Features:
Millionfold tried and tested
Exceptional value for money
Very quiet running
Excellent value for money