This part uses the following part numbers: Ariston - 998447 The part is compatible with the following boilers: Ariston Microsystem 21 RFFI Ariston Microsystem 21 RI Ariston Microsystem 28 RFFI Ariston Microsystem 28 RI Ariston T2 23 MFFI Ariston T2 23 MI Ariston T2 27 MFFI Ariston TX 23 MFFI Ariston TX 23 MI Ariston TX 27 MFFI
