Product review (5 stars): Best value for low volumes
This filter in a single stage exterior head (GXRLQ) works fine for under counter small home kitchen service.
It lasts 4 months supplying drinking and cooking water. For higher volume applications use twin head system and FQSLF filters. I estimate that arrangement would go six months undercounter vs. four with the single GXRLQR.
The end "R" denotes replacement filter.