Product review (5 stars): Perfect replacement for 4396508P
Purchased this to replace the 4396508P filters I have been using until now in my 12 yr old Whirlpool Gold side-by-side.  Based on the reviews I read here about fitment issues and soapy taste, I was hesitant!  At the same time, no way am I going to save a couple bucks and buy aftermarket knockoffs made somewhere in Asia.  We drink a lot of water and want to be sure what we're putting into our bodies is safe!
Upon receipt of the new filter. pulled out my existing PUR 4396508P and compared the size to these.  Exact match!
Installed the new filter and ran about 4gallons of water through, as stated in the instructions.  Drank a glass of water, perfect!  No aftertaste, no chemicals. Not soapy.  Just. Water.
Were these cheap? No. Especially compared to aftermarket filters.  But when put into perspective, a 2 pack will last about a year.  Break down the cost over the year, and I'm fine with that and the piece of mind it brings.