If you ever have to replace your under the sink GE filter (specifically the GE GXULQR), be ready for a frustrating ride.
It looks like this:
It is billed as the "Twist and Lock" Replacement Filter, the inside female hex socket sometimes rotates out of alignment when you remove the old filter. If this happens, there is no easy fix. Moreover, since the receiving head is generally under a sink or in some place you can't easily access, it is very frustrating when you are pushing into the plastic receiver and the new filter doesn't fit. (It is extra frustrating if you have a cast on a broken right hand, carpal tunnel in the your left hand and can't bend your back due to a herniated L5/S1.)
The instructions only say to "Push filter into the filter head/bracket. Turn filter 1/4 turn to the right until it stops. The top surface of the filter will be flush with the bottom of the filter head/bracket when fully installed." This only works if everything is properly lined up. The solution is to re-align the receiver by making a new tool from the old filter. By cutting off the head of the old filter (I used an angle grinder), and hammering in a flathead screwdriver, you have a custom alignment tool that looks like this:
How far should you rotate it? Enough to get the socket to line up so the flanges align. For me, this meant the top of hex was flat. The biggest challenge is knowing how hard to turn. I still don't know the internal mechanism, and the casing is all plastic and I didn't want to break it. For me, I had to rotate it pretty hard before it turned. This was a little scary because water started to leak out from inside. However, after my wife rotated in the cartridge (two hands were necessary, and a cast doesn't help), everything seems to be working fine.
Hopefully, this spares you some frustration.