Omnipure K Series have varied fitting types. They are included beside the cartridge number and are displayed as JJ, BB or SS
The Fittings refer to the type of connection at either end. The first letter relates to the input connection, and the second letter is the output connection. The input and outlet fittings are generally the same on your water line.
JJ Fitting - The JJ Fitting is suitable for 1/4" Quick Connect that do not require a screw-on fitting , or an Elbow (90 degree fitting)
BB Fitting - The BB Fitting is suitable for connection 1/4" Connection that already has a screw on Fitting at either end.
SS Fitting - The SS Fitting is a 90 Degree Single Female Fitting, otherwise known as an Elbow Fitting.
Sometimes the connection required is marked on your line connectors. They will be marked as JJ, BB or SS. It is recommended that you check your connection for these markings if you are unsure of the fitting required.
The images below display the different Fitting Types