Richard: The original was a "Aqua City AIM 1" from Campbell, CA but they cost way to much. It is 1 gpm.
These filters are essentially the same==>
1. Pentek GS-6 Extra .25 from the RV water filter store in Eugene, Or (602) 625-1875
2. Aquafresh WF270 from filtersfast.com
3. Omnnipure K23AC from espwaterproducts.com
I keep the quick disconnect plumbing ends and just move them to the replacement filter. Really easy to change on our model coach.
Larry