The Waterdrop WD-4035 is compatible with following model numbers:
Aquasana
AQ-4O35 and AQ-4O25 and will fit in the following systems: AQ 4500, AQ 4501, AQ 4000, AQ 4050, AQ 4055, AQ 4601, AQ 4600, AQ 4000W, AQ 4000P, AQ 4000B, AQ 4601.55, AQ 4601.62, and AQ 4601.56.
**The above brands do not source or sponsor the water filter. The manufacturers' names and model numbers have been used for reference purposes only.