Atla Water Systems purchased after January 28th, 2013 (Models AWS-A305, AWS-A300, AWS-RES & AWS-COM)
Does your system have one (1) white purification module comprised of three (3) filters?
If yes, your system uses Filter Set FS300.
Atla Water Systems purchased before January 28th, 2013 (Model # AWS-A200)
Does your system consist of four (4) independent modules?
Are the white purification filters split into one (1) double unit and one (1) single unit?
If yes, your system uses Filter Set FS200.